DeAndre Mathieu had just missed his second layup of the game, and the frustration was obvious.

The Gophers' 5-9 point guard wasn't finding the same openings at the hoop Wednesday against Penn State that he had found regularly through the nonconference schedule. He wasn't getting the same foul calls. And without that same efficiency, Mathieu — shaking his head after each missed opportunity — simply looked lost during the first half.

He can't afford that look on Saturday.

One game after taking on dynamic Penn State point guard Tim Frazier, Mathieu — who rallied with a strong second half against Penn State — will have his hands full Saturday with Michigan State floor general Keith Appling, a 6-1 senior who had 20 points, six rebounds and seven assists in a big win over Ohio State on Tuesday. The do-it-all guard seems to have taken his game — and his team — to the next level this season. Through 15 games, Appling, who has always been a defensive force, is averaging 15.9 points to go with 4.7 assists.

Gophers coach Richard Pitino said he has to have a big game from Mathieu, a former junior college player who has worked his way from a bench warmer at Morehead State to starting point guard on a Big Ten team.

"DeAndre is certainly going to have his hands full," Pitino said Friday. "I think he's excited about the opportunity. He's the type of kid who's got a big chip on his shoulder, and we've got to make sure he understands that it's not about him proving he's one of the best point guards in the conference but just sticking to the game plan."

Appling might play a bigger role than normal for the Spartans, because Adreian Payne (sore foot) and Travis Trice (flu) are listed as questionable for Saturday's game.

"What he's done is embraced what he is — a great defender who runs a team, and that's what he does," Spartans coach Tom Izzo told CBSDetroit. "He's improved his shooting each year, but he's not a kid that's going to come out and be trying to drain any threes or anything like that. … He plays within himself, and I think he tries to be nobody but what he is. That's a pretty good start in this day and age."

Mathieu is still adjusting to life at the highest level of college basketball. But the undersized guard also doesn't shy away from the challenges.

"I'm trying to go out every night and go against some of the best point guards in the country and try to prove that I belong here," Mathieu said. "That I'm good enough to play in the Big Ten."

In the Gophers' opener against Michigan, Mathieu committed a series of damaging turnovers (he had five overall), including two in the final 1:49. But in the two games since, Mathieu has turned the ball over just three times. Against Purdue, he went to the bench with two fouls less than six 5 minutes into the first half but returned smarter and more contained in the second, finishing with 11 points and four assists.

And after a rough first half against Penn State, Mathieu played the role of hero in the second, lifting the Gophers with 14 second-half points and four rebounds, and getting the critical steal with 43 seconds left, swiping the ball from John Johnson at midcourt and racing in for a layup.

"I was really tough on DeAndre at halftime," Pitino said. "I just thought he wasn't playing well, and it totally affected his attitude on the court, his body language. I jumped him pretty good at halftime, and he responded and was great in the second half."

Mathieu has emerged as a major piece of Pitino's new up-tempo offense and pressure defense. Mathieu knows just what's expected of him: Avoid the sort of first half he had against Penn State, and the finish he had against Michigan.

"I've just got to make better decisions, think better," Mathieu said. "No one wants to make those mistakes [like those against Michigan]. They were crucial mistakes, though, and it really hurt so I kind of beat myself up for it. But I'll get better."