You have to wonder when Iowa coach Kirk Ferentz knew it was over.

Was it after Michigan quarterback JJ McCarthy connected with Donovan Edwards on a 12-yard touchdown to make it 20-0? Was it when Blake Corum scored his FBS-leading 10th rushing touchdown on a 20-yard scamper in the 4th quarter?

Maybe it had nothing to do with Michigan’s offense totaling 327 yards en route to a 27-14 victory at Kinnick Stadium. On most days, that would be a strong enough showing for Iowa to feel content heading into the closing minutes. Then again, when the offense can’t move the football, is 327 yards too much?

Phil Parker’s defense has often been the catalyst for success in Iowa City. Games that could have been lost at halftime ended up swinging in favor of the Hawkeyes after the break But turnovers are usually part of the equation, and Saturday there were none.

A well-oiled Michigan offense pushed its way through the Hawkeyes’ defense, meeting some resistance but no chaos. While Iowa held the Wolverines to a season-low 27 points, there were plenty of moments when the cracks expanded well past what could’ve been imagined.

Entering October, Ferentz knew what his offense could do. More specifically, he knew what that unit couldn’t do. That pressure was added to Iowa’s defense to make critical stops and splash plays. Unfortunately, the unit didn’t meet the challenge.

It wasn’t as if Michigan won with explosive plays downfield. Iowa simply couldn’t pressure McCarthy into making mistakes. Outside of a few drives, the Wolverines owned the time of possession, and with it, controlled the game. Even when drives ended in punts, Michigan never wavered in its confidence.

By the time Iowa’s offense found its rhythm, the damage was done. The Wolverines were up 20-0 when Hawkeyes running back Kaleb Johnson scored a 2-yard touchdown to begin the fourth quarter. And with the way Iowa’s offense has looked this season, a 2-score lead was more than enough to coast on through the final 15 minutes.

Blame the offense if you please. Spencer Petras finished 21-of-31 passing for 246 yards and a touchdown. Michigan recorded 4 sacks, but it also allowed 16 first downs. If one were to point fingers, the blame should be on the run game. Iowa entered Week 4 averaging 134 yards per game, but totaled only 35 on 1.5 yards per attempt on Saturday.

What ended up costing Iowa a chance to go 6-1 against top 5 teams at home was its inability to force negative plays. Michigan only had 2 plays go backward, one of which came on a sack from Deontae Craig for a loss of 21 yards. The other? A 1-yard loss against Corum in the 4th quarter.

Is Iowa’s season dead in the water? In a sense, no. Thanks to a 20-10 win by Purdue, Minnesota suffered its first loss of the season. Wisconsin is out of the B1G West running barring a miracle following a loss to Illinois. And while the Boilermakers might take the lead in the division, there are questions surrounding its offense nearing the halfway point of the regular season.

Ferentz knows where his team is limited. Against bad teams, the Hawkeyes’ defense can take its foot off the gas. Against good teams, it can play cautiously so long as the offense has a chance to put up points.

Against great teams, allowing 300 yards is too much. Heck, 200 yards might be enough for a team to feel cozy going against this offense. It showed on Saturday against Jim Harbaugh’s roster.

More than likely, it’ll show again against another team before the season’s end.