Here are three things we learned about the Purdue game, two questions we have moving forward and one bold prediction about the future as the Wildcats prepare to travel south and face Illinois.

1. It was a fitting end for the old Ryan Field.

If that was indeed the final game in the current iteration of Ryan Field as is expected, it was just about perfect.

Northwestern came in riding high at at 5-5, just a win away from bowl eligibility, after dismantling Wisconsin on the road the previous week, and David Braun had been promoted to full-time head coach on Thursday. The scene was set for a special day at the corner of Central and Ashland. It delivered.

Things started fast, with Northwestern forcing a Purdue three-and-out to start the game, punctuated by a sack shared between Xander Mueller and Anto Saka. The Wildcat offense responded quickly, scoring in four plays on an untouched seven-yard scamper from Cam Porter following a 35-yard strike from Ben Bryant to AJ Henning.

Then everything came to a screeching halt. Purdue ran all over the Northwestern defense, but couldn't put up any points as Northwestern's offense sputtered. The Wildcats took a 6-0 lead into the break.

A TJ Sheffield muffed punt set the Cats up with the ball at the Purdue 21-yard line in the third quarter, and Jack Olsen converted a 30-yard field goal to end that drive. Purdue responded with a shifty 20-yard touchdown run from Tyrone Tracy Jr.

Then, the NU offense came to life. Bryant perfectly read a corner blitz and found Cam Johnson in the vacated space, who left Dillon Thieneman grabbing at air as Johnson raced 52 yards to the end zone. On Northwestern's next possession, Porter took a third-and-7 handoff 34 yards for a score to put Northwestern up 23-7 with 12 minutes left. Should be easy from there, right? It never is.

Fittingly, after a Bryant interception and a Purdue touchdown and two-point conversion to make it a one-score game, Northwestern's defense was asked to save the day and close out a win, just as they have been so many times in Ryan Field. On Senior Day, a senior, Mueller, picked off Purdue quarterback Ryan Browne with 21 seconds remaining to seal the win and send the Cats bowling.

It really was a vintage Northwestern ending. They made it harder than it had to be, and it all came down to the Wildcat defense making one more stop. The defense did just that one final time.

As fans stormed the field to celebrate the win and bowl eligibility, the reality of how improbable Northwestern's 2023 season has been began to set in. A team that was 4-20 over the last two seasons, endured a scandal and coaching change in July and had a Vegas win total of 2.5 before the season, is going to a bowl game. It's impossible to overstate how incredible that accomplishment is.

Northwestern's players and coaches could've quit and started looking forward to new beginnings elsewhere at innumerous points in 2023. They never did. Everyone in the program banded together and never stopped giving it everything they had to get to that moment. Whether it was having their coach fired over zoom a month and half before the season, or being down 21 to Minnesota entering the fourth quarter a week after losing by 24 to Duke, or losing their quarterback for four games, or heartbreaking losses to Nebraska and Iowa, Northwestern never wavered. The Wildcats kept picking themselves back up and will be rewarded with a 13th game for their tireless persistence.

For this Northwestern team to win their sixth game and clinch a bowl game in front of the largest home crowd of the season in the final game at old Ryan Field was really a special moment for everyone in and around the program. A Hollywood script writer couldn't have written it much better.

Saturday wasn't always perfect, and certainly wasn't pretty, but it will hold a special place in the Northwestern football community's heart. Just like old Ryan Field.

2. Northwestern's defense bent, but didn't break.

Despite only giving up 15 points, it was not a banner day for Northwestern's defense. Purdue ran all over the Wildcat defense to the tune of 303 yards on the ground. The Boilermakers were led by 160 yards by Tracy, on 10 yards per carry; Browne added 85 yards of his own, and Devin Mockobee tallied 54 and a touchdown.

In total, Purdue rung up 443 yards on NU, but Braun said it best after the game: "yards don't result in wins; points do."

When their back was against the wall, Northwestern's defense delivered repeatedly. On Purdue's second drive of the game, a Carmine Bastone strip sack stalled Purdue's offense and forced a 44-yard field goal attempt, which was missed.

On Purdue's next drive, the Boilermakers had second-and-1 from the Northwestern 14-yard line. Bastone blew up a run to Tracy, who after review was determined to have stepped out after no gain. On third-and-1, Ore Adeyi and a host of other Wildcats met Tracy in the backfield for a loss of a yard bringing up fourth down. Needing only two yards, Purdue opted to go for it. Again Tracy got the ball and he was drilled at the line of scrimmage by Mueller who came flying downhill and got the defense off the field.

The magnum opus of the NU defense's first-half heroics came on Purdue's next drive. A Browne scramble gave Purdue the ball at at the Northwestern 1-yard line on second-and-goal. The first play was a flip to Deion Burks that Northwestern strung out beautifully, forcing a loss of one. Tracy got the ball up the middle on third down and had nowhere to go. On fourth down, Tracy tried to pound it in again, but he was stood up by PJ Spencer and Rod Heard II, completing the goal line stand and keeping Purdue scoreless. In the celebration, Heard looked to the Purdue sideline and gave the Boilers a Dikembe Mutombo finger wag, a fitting celebration for a Northwestern defense that kept sending back every proverbial Purdue shot at the rim.

On Purdue's next drive, Bennett Meredith and Tracy botched an exchange and Richie Hagarty jumped on the loose ball at the NU 40-yard line. Garnett Hollis Jr. added an interception to end the first half, too.

Even on Purdue's second scoring drive of the second half, Tracy ripped off a 62-yard run, but an outstanding effort from Hollis to chase the running back down from the other side of the field and drag him down at the 7-yard line forced Purdue to use nearly three more minutes before finally punching it in.

All in all, Northwestern has plenty to work on defensively. The Cats missed far too many tackles and let quarterback scrambles hurt them all game. Despite those struggles, Northwestern's defense did what good units do: make plays when their team needs them. The Cats defense forced three turnovers, and a staggering six Purdue drives entered Wildcat territory but ended with no points. That's why Northwestern was able to win on Saturday.

3. Braun isn't the only newcomer who can coach.

Braun has garnered a ton of praise for his work, and rightly so, but Northwestern has plenty of other new coaches who have done an outstanding job.

Defensive line coach Christian Smith has taken a Wildcat defensive line that was a weak spot last season and turned it into one of the strengths of the defense. Under Smith's tutelage, former walkons Bastone and Spencer have become legitimate Big Ten contributors at defensive tackle. Young defensive ends Aidan Hubbard and Saka have become forces getting after the quarterback. FCS transfers Hagarty and RJ Pearson have adjusted to playing Power Five football just fine. True freshman Michael Kilbane has taken on a bigger load as the season has gone on and gotten better each week. That's not to mention the contributions of veterans like Sean McLaughlin, Jaylen Pate and Najee Story. If that seems like a lot of names, it's because it is. Almost every defensive lineman on Northwestern's roster contributes, and that's a testament to Smith's coaching and ability to get his whole room ready for Saturday.

Another position group that has done an about-face is the wide receivers under new coach Armon Binns. The Wildcats big three off Henning, Johnson and Bryce Kirtz combined for 10 catches for 208 yards and Johnson's touchdown on Saturday. Those three are now up to 118 catches for 1,490 yards and 11 touchdowns on the season. Northwestern has struggled to run the ball for extended periods in 2023, but that starting trio has been reliable and kept the offense afloat all year under Coach Binns.

New cornerbacks coach LaMarcus Hicks has Hollis and Theran Johnson playing physical and aggressive football on the outside, making life difficult on opposing receivers. Adeyi has also gotten more involved as the season has gone on. New running backs coach Chris Foster finally saw Porter break through these last two weeks with 167 yards and two touchdowns. Redshirt freshman Joseph Himon II is averaging 14.5 yards per reception as a massive weapon in the screen game, as well.

Braun steals the headlines, but all of Northwestern's new coaches have made a sizable impact in the program's turnaround.

1. Can Northwestern get The Hat back?

Northwestern owned the series against in-state rival Illinois for a while. From 2015-2020, NU won six in a row against the team from downstate, outscoring the Illini by an average of 31.5-11.3. The worst beatdown came in a 42-7 thrashing in Champaign in 2017.

Since Bret Bielema took over the Illini program, though, the script has completely flipped. Illinois has dominated Northwestern the last two years, winning by a combined total of 88-17.

To say Northwestern will be looking to put an end to that is an understatement. The Wildcats have had their best season since 2020 by a longshot and hope to cap the regular season by bringing the Land of Lincoln Trophy back to Evanston.

"When I mentioned something about that in our locker room after the game, there was an energetic group that fully understands that we have one opportunity left in the regular season, and it's a big one," Braun said of the rivalry game to close out the season.

If a chance to bring the hat back north isn't enough, Illinois will enter the game at 5-6, needing to beat Northwestern to find themselves in a bowl game. A chance to end their rival's season on the road should surely have Northwestern extra motivated.

2. Has Northwestern found some balance on offense?

Northwestern has had to operate without a running game for much of 2023, but some balance has been restored over the last two weeks. Porter has run for 167 yards the last two games on 4.8 yards per carry. In Northwestern's previous three games, Porter had just 83 yards on a measly 2.7 yards per carry.

Northwestern's offensive line struggled a bit on Saturday as Bryant was sacked six times, though a couple were on Bryant for holding the ball too long. The big guys up front have done a much better job opening up holes over the last two weeks, and Porter has taken full advantage.

On the season, Illinois is allowing 150.4 rushing yards per game, 12th in the Big Ten. As a team Illinois has 22 sacks on the season, which ranks 10th in the Big Ten, but the Illini pass rush is led by future first round NFL draft pick Jer'Zhan Newton. Being able to run the ball and slow down Illinois' pass rush will be key to keeping Bryant upright and healthy in Champaign.

Both Bryce Gallagher and Xander Mueller will make All-Big Ten teams.

As is tradition in Evanston, a good Northwestern defense is led by its linebackers. The senior duo of Bryce Gallagher and Mueller have played their best football as the season has gone on and been key cogs in NU allowing only 15.8 points per game since the bye week.

Gallagher's 102 tackles ranks second in the Big Ten, and Mueller isn't far behind in sixth with 93. Mueller's 10 tackles for loss are good for eighth in the conference, and his five sacks rank 15th.

Gallagher has also grabbed an interception, forced two fumbles and recovered one. Mueller has snared a pair of picks, most on the team, including the game-sealer on Saturday. Each has a game with 19 tackles, Gallagher against Rutgers and Mueller against Iowa.

Both veteran linebackers are tackling machines, but the stats don't tell the whole story. Gallagher is the unquestioned leader of the team, and Mueller is another veteran who has helped guide the younger players on defense. Together they have spearheaded the turnaround in Northwestern's defense, and their efforts will be recognized with All-Big Ten honors come season's end.