IOWA CITY, Iowa -- The Iowa Hawkeyes began Big Ten play in style Tuesday, upsetting top-ranked Michigan State 83-70 inside a sold-out Carver-Hawkeye Arena.

The Hawkeyes snapped a nine-game losing streak to the Spartans and posted their first win over a No. 1-ranked opponent since defeating Connecticut during the 1999-2000 season.

"It was a great opportunity for us," said Iowa senior guard Mike Gesell, who scored a game-high 25 points. "It's a steppingstone, a way to start the Big Ten off right.

"It does feel good to finally beat them. I had never been able to beat them in my career, and that's a very good team."

In previous meetings with Michigan State, Iowa wilted during the second half. That didn't happen this time around. Gesell led the charge, scoring 17 second-half points. Overall, he shot 7-for-10 from the floor and 11-for-13 from the free-throw line.

"His decision-making was really incredible because you don't have a lot of opportunities to drive against that defense," Iowa coach Fran McCaffery said. "He was getting it to the rim, and he was getting them in foul trouble."

The Spartans found success inside with senior forward Matt Costello, who finished with 17 points on 6-of-8 shooting and also tallied a team-high seven rebounds. However, they couldn't hit anything from outside, finishing a meager 3-for-13 from beyond the 3-point arc.

Michigan State junior guard Eron Harris managed to finish with 21 points, but he fouled out in the closing minutes.

Compounding the problem was that Michigan State committed 16 turnovers that led to 21 Hawkeyes points. Tom Izzo, who coached for the first time since the passing of his father, Carl, was disgusted by his team's overall effort and wouldn't use the absence of senior guard Denzel Valentine as an excuse.

"Iowa played awfully well," Izzo said. "One of the rare times in my career where I thought we got, for lack of choice of a better word, punked. We got out-physicaled, we got outhustled. They got every loose ball.

"Give them credit. Take nothing away from them. Give us blame. That wasn't a disappointing loss. It was a disappointing effort."

Echoing his coach's words was senior guard Bryn Forbes, who was completely negated by Iowa, scoring only three points and picking up four fouls in 28 minutes.

"I think we just had a lot of effort-related mistakes, you know, mental lapses," Forbes said. "They were getting loose balls that we usually get that we just didn't come up with today because of effort."

While Michigan State struggled from 3-point range, Iowa prospered. The Hawkeyes went ahead by as many as 19 points midway through the second half when junior forward Peter Jok drained a pair of 3-pointers to extend the lead to 58-39.

Jok finished with 19 points.

"(Iowa guard Anthony) Clemmons told me, 'Just be ready because I'm going to find you,'" Jok said. "I was trying to be ready, and they found me."

The game began with both teams shooting the ball well. The Spartans made six of their first 10 shots, while the Hawkeyes connected on five of their first eight. Both teams then began to clamp down defensively and held the other under 40 percent shooting for the entire first half.

The scoring remained low until midway through the half when Iowa went on a 10-0 run to go up 31-17. The surge began when redshirt freshman walk-on forward Nicholas Baer drained a 3-pointer to extend the Hawkeyes' lead to seven points. It ended with sophomore forward Dom Uhl banking in a 3-point bucket. Baer and Uhl combined for 16 of the Hawkeyes' first-half points and 18 points overall.

Both teams play their next game on the road Saturday. Michigan State travels to Minnesota, while Iowa visits No. 14 Purdue.

NOTES: Michigan State sophomore F Marvin Clark Jr., made his first start of the season, replacing sophomore F Javon Bess in the lineup. Clark, who started seven games for Michigan State last season, scored seven points Tuesday. ... The game marked the third time in Fran McCaffery's six-year tenure Iowa has played against a No. 1-ranked opponent. The last encounter was in 2012-13, when the Hawkeyes lost at No. 1 Indiana, 73-60. ... Before Tuesday, the last time Iowa played host to a top-ranked team was in 2004-05, when Illinois visited Carver-Hawkeye Arena. The Illini won 75-65. ... The Spartans opened league play on the road for the 10th time in the past 15 seasons. Conversely, this was the fifth time in the six seasons Iowa opened the Big Ten portion of its schedule at home.