On Monday, Michigan State was voted No. 1 for a fourth straight week in the Associated Press poll. One day later, the previously undefeated Spartans walked out of Carver-Hawkeye Arena, double-digit losers to Iowa in their Big Ten opener.

“We got, for a better choice of words, punked,” coach Tom Izzo told the media afterward, arms folded, eyebrows raised.

The loss came with injured star Denzel Valentine on the bench for the second consecutive game. He will be sitting there again Saturday at Williams Arena when the Spartans and Gophers tip off. Just how big of a loss is Valentine to Michigan State?

On paper, the impact is big enough. Without Valentine — who injured his left knee in a practice and had a minor knee scope surgery on Dec. 21 — Michigan State (13-1) loses 18.5 points, 8.3 rebounds, 7.1 assists per game and a perpetual triple-double threat.

In practice, the 6-5 senior’s influence is much greater.

The dynamic point forward is the glue in Michigan State’s ultra-efficient offense. His length and athleticism paces the Spartans’ stifling defense. Despite his size, he dominates on the boards on one of the 10 best defensive rebounding teams in the country. Off the court, Izzo has touted Valentine’s effect in the locker room and in hotels on the road.

With him on the bench Tuesday, the Spartans never led in Iowa City, shot only 3-for-13 from three-point range, collected 12 assists on 27 field goals and allowed the Hawkeyes to stay on top by 10 or more points throughout the entire second half. Spartans center Matt Costello said afterward that several guys “fessed up” to losing focus.

Valentine’s presence, or lack of it, was most evident in the Spartans final two nonconference games, too. At Northeastern on Dec. 19, Valentine scored 17 points and the Spartans won by 20 to match the best start (12-0) in school history. Three days later without him, Michigan State needed overtime at home to scoot past Oakland.

Indeed, there might be no player in the country that means more to his team than Valentine does to Michigan State.

That’s good news for the Gophers, although Izzo’s cupboard isn’t exactly bare without Valentine. Costello is a sizable presence inside who can block shots and post up, or step out for the occasional three-pointer. Bryn Forbes can break out offensively — the senior guard piled up 32 points in the overtime victory over Oakland, but he followed that by scoring only three points against Iowa. West Virginia transfer Eron Harris, starting for Valentine, has combined for 48 points in the past two games, his two best scoring efforts at Michigan State.

“Costello is a good post player who has been good in this league for a long time,” Gophers coach Richard Pitino said in an e-mail. “Harris and Forbes present a lot of challenges on the perimeter.”

Even so, Saturday’s game will have a big asterisk. Michigan State can win sans Valentine, who is expected to miss another couple games, but his absence makes the game a little bit more of a fair fight.

Tuesday, Izzo said his team was “outphysicaled and outhustled,” and said that Valentine’s injury was no excuse. Those are the words of a smart coach, but Spartans basketball isn’t the same without its star.

BASKETBALL BREAKDOWN

Game of the weekend: No. 9 Butler at No. 6 Xavier, noon Saturday (FS1)

The Big East hasn’t wasted any time getting our attention with four teams sitting in the top 16. But these two schools are both trying to counter losses to open conference play: Butler to Providence, Xavier to Villanova.

By the numbers

57 Consecutive games that Clemson has dropped at North Carolina after falling 80-69 on Wednesday. The Tigers have never won in Chapel Hill.

20 Years since a player averaged at least 13.1 rebounds and 5.8 assists for a season, which is what LSU freshman Ben Simmons is averaging now.

Final thought

After being hyped all fall, Maryland simply isn’t there yet. Sure, there’s a lot to like. The Terrapins are led by one of the more aggressive and dynamic guards in Melo Trimble, and freshman center Diamond Stone might be preparing for liftoff. But in the Big Ten opener vs. Penn State, Maryland slugged through bouts of lifelessness and carelessness and was down eight at halftime. At 12-1, the Terrapins have produced the results, but it seems nothing will come easy in the next two months.

Big Ten power rankings

Michigan State (13-1, 0-1): Plenty of opportunities to brush off the Iowa loss with games vs. the Gophers, Illinois and Penn State next.

Purdue (13-1, 1-0): We will find out more about this team when two underrated foes, Iowa and Michigan, visit this week.

Iowa (10-3, 1-0): The Hawkeyes looked great in upsetting Michigan State. Suddenly, that exhibition loss to D-II Augustana seems far away.

Maryland (12-1, 1-0): Without freshman Diamond Stone’s massive game, the Terps might have lost at home to Penn State.

Michigan (11-3, 1-0): Outta-nowhere sophomore Mark Donnal led the team with 26 points and nine rebounds against Illinois.

Ohio State (9-5, 1-0): Youth was very apparent in an up-and-down performance vs. the Gophers, but a 20-3 run late got it done.

Northwestern (13-1, 1-0): Can they keep the momentum going in a home date with Maryland?

Indiana (11-3, 1-0): A seven-point victory over lowly Rutgers doesn’t mean much. The Hoosiers will have to do more.

Illinois (8-6, 0-1): Khalid Lewis joined the long list of the Illini’s sick and wounded, sitting out a 78-68 loss to Michigan with the mumps.

Penn State (9-5, 0-1): Penn State had an eight-point lead at the half before falling to the No. 4 team on the road (Maryland) by just six.

Wisconsin (8-6, 0-1): Interim coach Greg Gard’s first loss was going to come sometime. He got it out of the way vs. Purdue.

Nebraska (8-6, 0-1): The Huskers have been in a win, loss, win, loss holding pattern for over a month.

Gophers (6-7, 0-1): Jordan Murphy has emerged as the key player, but he has to stay out of foul trouble.

Rutgers (6-8, 0-1): With three road games in the next four, the start of 2016 is not welcoming for coach Eddie Jordan and Co.