With its Rose Bowl hopes on the line Saturday, Northwestern was forced to take its medicine — a cold dose of reality.

After three consecutive victories put them atop the Big Ten standings, the No. 17 Wildcats were trounced 41-28 by No. 21 Purdue before 41,053 at Ryan Field on Homecoming, with the streaking Boilermakers outscoring NU 20-0 in the third quarter and completely foiling the Cats’ game plan.

As advertised, the two top scoring teams in the Big Ten came out of the locker rooms primed for an offensive explosion. Both teams combined to score three touchdowns in the first eight minutes as NU took an early 14-7 lead. But from the middle of the first quarter on, Purdue put a stranglehold on the Cats, employing an aggressive defensive scheme that held NU tailback Damien Anderson to a mere 55 yards.

“I don’t know what happened at the 14-7 mark,” coach Randy Walker said. “Sometimes you wonder, when you get a couple bang, bang like that that (if) it gets a little easier than you want it to be.

“I don’t know if that happened today, if we hit a lull in the storm. But we lost momentum pretty significantly there in the first half and never really got it back.”

Though Purdue quarterback Drew Brees’ arm and wide receiver Vinny Sutherland’s crossing routes were clicking, NU’s downfall came on mental mistakes and turnovers. The Cats were whistled for 12 penalties totaling 106 yards. And in the disastrous third quarter, they turned over the ball three times in seven minutes.

With the loss, NU (5-2, 3-1 Big Ten) fell into a four-way tie for first place in the conference with Michigan, Minnesota and Purdue, which all have identical records. The Cats have a bye next week before traveling to face the Golden Gophers on Oct. 28.

NU endured a terrible stretch on a second-quarter drive when, after a 10-yard sack on first down, it was flagged on consecutive plays for false starts. Then quarterback Zak Kustok was brought down again in the backfield, pushing the ball back to the Cats’ 6-yard line. Fittingly, Anderson had his longest carry of the day — a 14-yarder — the following play on 3rd-and-34.

“We were getting behind the chains and then we were trying to dig ourselves out of a hole,” said Kustok, who threw for 260 yards and two scores. “It seems like we were doing that a lot of times today and that’s what I think really hurt us.”

On three consecutive possessions in the third, NU handed the ball back to the Boilermakers, who cashed in with 13 points to put the game out of reach. Trailing 21-14, the Cats thought they got a huge break when J.J. Standring’s punt caromed off the leg of a Purdue player and was recovered by Ronnie Foster at midfield.

But disaster struck the next play when Kustok’s pass bounced off receiver Roger Jordan’s hand and right to Boilermakers safety Ralph Turner, who made the interception. Three plays later, Brees found a wide-open Sutherland on a swing pass for a 26-yard touchdown.

“I have to give a lot of credit to Purdue, they popped the ball and took balls off of us and we didn’t get many back,” Walker said. “We lost that turnover ratio significantly.”

Brees finished the day 22 of 40 passing with five touchdowns and 239 yards. He was aided by running back Montrell Lowe, who racked up a career-high 174 yards on 26 carries. It was also Purdue coach Joe Tiller’s first win over a ranked opponent on the road in eight tries.

After the early scores, NU’s offense went silent as Purdue dominated the line of scrimmage, plugging running lanes that Anderson zipped through in previous games.

Purdue also had a strong counter to NU’s no-huddle offense.

By wearing wristbands containing their defensive plays, the Boilermakers had no need to huddle and were always ready for the ball to be snapped.

After totaling 685 rushing yards in his previous three games, Anderson was held to his lowest output since last October, when Minnesota limited him to 48 yards.

“Every team we’ve played this year has tried to do something to stop our run,” center Austin King said. “Whether they slam one guy, whether they slam another guy, whether they twist. And before today, five out of six times we had an answer for it.”

With the Cats eying Brees and speedy receivers Sutherland and John Standeford, Lowe made his presence known on the Boilermakers’ second play of the game, busting through the defense for a career-long 50-yard run.

“He’s a good back and we all knew that, we all saw it in tapes that we watched before this week,” linebacker Billy Silva said. “That was the defense’s fault, we didn’t play our gaps correctly and he found the open gap, he found where we messed up and that’s what a good offense is going to do to you.”

NU’s loss coupled with Minnesota’s stunning upset of Ohio State assured that no team will escape the Big Ten season undefeated.

Following this weekend, five teams have one conference loss, making the Rose Bowl picture as hazy as the Los Angeles skyline.

“I think there is a lot of football left in this Big Ten season,” Walker said. “Based on what happened in Columbus today, we’re still right there and that’s what I try to tell our guys, there’s a lot of goals we have that are still on the board.”