Freshman Tom Nichol kicked three field goals and Iowa's defense stopped the Big Ten's best rushing team as the Hawkeyes defeated No. 5 Michigan, 9-7, yesterday in Ann Arbor, Mich.

Iowa, ranked 12th, improved its overall record to 5-1, and took over first place in the conference with Wisconsin's loss to Michigan State. Michigan is 4-2 overall and 2-2 in the conference.

The Wolverines, who had not lost to Iowa since 1962, entered the game averaging 278.8 yards rushing per game, and had the conference's leading ground gainer in Butch Woolfolk (167.6 yards). Iowa held Michigan to 155 yards on the ground and limited Woolfolk to 56 yards in 14 carries in stopping at eight games his streak of 100 or more yards rushing.

Michigan Coach Bo Schembechler, aware that chances are remote for his team to repeat as conference champion and return to the Rose Bowl, blamed the defeat on his offense, which he said failed to block.

"We are going to play football for the fun of it from now on," he said.

Nichol kicked field goals on Iowa's first two possessions to give the Hawkeyes a 6-0 lead.

In the third quarter, which began with Michigan leading, 7-6, Iowa defensive back Mel Cole intercepted a pass intended for tight end Craig Dunaway in the end zone, and the Hawkeyes went 67 yards in 12 plays. Nichol kicked a 30-yard field goal that put them ahead for good.