Northwestern's losing streak reached 13 games with a 68-51 loss at home to No. 21 Wisconsin on Sunday night at Welsh-Ryan Arena.

While 13 is considered an unlucky number, luck has nothing to do with this streak. Northwestern got here through a lack of aggressiveness on offense, an inability to rebound, defensive lapses and turnovers.

Northwestern got out to a good start in this rematch with the Badgers. Boo Buie looked like his old self early and scored the Wildcats first seven points.

A Robbie Beran triple put the Cats ahead 10-5, which would be their largest lead of the game. The teams traded buckets until a Ty Berry three gave Northwestern an 18-15 lead with 9:48 remaining in the first half.

Then Northwestern succumbed to its routine and went into a scoring drought. They didn't score for more than three minutes until a Pete Nance dunk was able to tie the score at 20. Northwestern then proceeded to embark on yet another three-plus minute scoreless string, putting them in a 34-24 hole at the break.

A Ryan Young and-one with 12:59 left in the game brought the Wildcats to within seven. But by the time the Wildcats scored again, over five minutes had elapsed and they found themselves down by 16. For good measure, Northwestern added in a nearly three-minute scoring drought in the final five minutes.

NU was led by 19 points from Buie, his highest scoring output in two months and a welcome sign from the sophomore who has struggled to find his shooting touch lately. No other Wildcat scored in double figures.

Wisconsin did essentially whatever it wanted offensively for the final 30 minutes of the game. Five Badgers were in double figures, led by Micah Potter's 19 off the bench.

Here are our takeaways from the loss that dropped Northwestern to 6-14 overall and 3-13 in the Big Ten:

Scoring droughts derail Cats: Northwestern's four major scoring droughts combined for 14 minutes and 45 seconds. That's 37% of the game.

As Northwestern has found out many times this year, it's hard to score when you have very few players who can create their own shot.

The Wildcats are limited in terms of talent on offense, and the problem only worsens with turnovers. Northwestern turned the ball over 14 times and the Badgers had a decisive 21-8 edge in points off of turnovers.

Buie played like his old self: Remember when Northwestern's sophomore point guard was averaging 18.3 points per game in Big Ten play on 66.7% shooting from beyond the arc and the Cats were ranked 19th in the country? That feels like an eternity ago.

Since his game-winning triple against Ohio State on Dec. 26, Buie has shot 25.9% from three and averaged just 6.8 points per game.

Buie's 19 points against Wisconsin were his most during the losing streak, and Northwestern needed all of them just to stay competitive because no one else, aside from Anthony Gaines, looked ready to play. The Wildcats other four starters -- Nance, Miller Kopp, Ryan Young and Chase Audige -- combined for just 17 points, two fewer than Buie.

Buie has the ability to get in a zone and put up points in bunches; he just needs to do it consistently. For Northwestern's sake, hopefully this is a springboard for Buie.

Kopp's regression continued: Kopp had another forgettable night and is going through the worst stretch of his career. While he's never been a particularly good defender or rebounder, what he could do is score points and shoot efficiently. He is struggling to do even those things anymore.

In Northwestern's last five games, Kopp is averaging 5.6 points per game on 27% shooting, including just 19% from long distance. Against Wisconsin, he finished with just four points on one-of-three shooting, with one rebound, three turnovers and four fouls.

Kopp is a spot-up shooter, so teams have just put good defenders on him to prevent him from getting clean looks. He has made it easy for defenses to take him out of games, and it's imperative that he gets better at creating his own shot and getting himself open.

It's disappointing for Kopp, who looked like he had such a bright future. Head coach Chris Collins has been tinkering with the lineups a lot lately and it might be time to shake things up again and see if a move to the bench can help get Kopp back in a groove.

Collins sets a new personal low: Collins made history on Sunday, but it's not the good kind.

Northwestern's 13th loss in a row is the longest losing streak of Collins' career. It's the third straight year his teams have lost 10 or more in a row, and his teams have dropped at least five in a row in seven of his eight seasons in Evanston.

Last year, the Wildcats' 12-game losing streak was written off as the result of a young team that lost close games due to inexperience. This year, they aren't all that young of a team anymore, yet they have a longer losing streak and are arguably worse this season.

Collins likes to say that his team is "close." The reality is that, with every game, Northwestern seems to get further away.