This past weekend was an exciting one for the Big Ten as the hunt for the conference championship starts to heat up.

The fight for the West is as hot as it has ever been as Northwestern leads the division, but three teams are just a half of a game behind.

On the other side, the East looks as if it will come down to Ohio State vs. Michigan.

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Here is a look at the top storylines from around the Big Ten this week:

Purdue is rolling

The Boilermakers might just be the second-hottest team in the Big Ten right now.

No, that’s not a joke, and it’s not even an overreaction to the Oct. 20 game.

Rewind back to the beginning of the season, when Purdue was many people’s dark horse.

After a few early season losses, everyone appeared to count the Boilermakers out, but now, they’re on a four-game winning streak after dominating Ohio State.

Don’t forget, they started the winning streak with a win over then-ranked No. 23 Boston College. It won’t be easy, though, to keep the streak alive this week as they head to East Lansing for a date with the Spartans.

“We are proud of the fact we were able to pull off that win,” Purdue coach Jeff Brohm said in a press conference. “With that, it’s one game and one win, and we have to move on to the next opponent, Michigan State.”

Ohio State defense

Dwayne Haskins is a great college quarterback, there’s no question about that, but the Ohio State defense has been a huge question mark.

The defensive deficiencies were exposed on Oct. 20, as Purdue went wild over the Buckeye defense for 539 yards and 49 points.

Injuries have been a big problem for Ohio State, and, of course, losing its best defensive player in Nick Bosa certainly doesn’t help. Head coach Urban Meyer isn’t too worried whether the team can bounce back.

“We have good players,” he said after the loss. “We lost a game last year and came right back, so we have good guys, and we’re going to work hard [on] what’s off and get this thing right.”

Is Northwestern a legit contender?

The Wildcats are probably the biggest head-scratchers so far this season. They beat Purdue on the road early, a win that looks substantial after last week. Two bad losses later, they almost beat Michigan before beating Michigan State in East Lansing the next week.

Then, just as it seemed Northwestern was starting to get it, it almost lose twice to the two worst teams in the Big Ten.  Yet, despite the up-and-down roller coaster of a season, Northwestern is a half game up in the West.

The Wildcats will have a chance to prove themselves in the next three weeks as they have No. 20 Wisconsin this weekend before taking on No. 3 Notre Dame and No. 18 Iowa in the following weeks.