Greene, who missed last season due to academic issues at a junior college, scored on a 1-yard plunge on the Hawkeyes' first possession, capping a 69-yard drive, and Iowa was on its way to an easy win.
The Hawkeyes overpowered the Black Bears (0-1) with 245 yards rushing, including a 19-yard TD run by Hampton on his first career carry.
Iowa led 22-3 at halftime and turned the game into a blowout in a 15-second stretch early in the fourth quarter. Paki O'Meara capped a 10-play-drive with a 1-yard run to make it 32-3, and after an interception by a Pat Angerer, Hampton scored to make it 39-3 with 14:43 left.
Hampton added a 22-yard TD run with 3:29 left, and finished with 68 yards on nine carries.
Jhamal Fluellen ran for 104 yards to lead Maine, which lost its fourth straight to a Football Bowl Subdivision team after winning at Mississippi State 9-7 in 2004. The 43-point loss was Maine's worst in seven meetings against FBS opponents.
Christensen started all 12 games in 2007 and had a tenuous hold on the No. 1 job after fall camp. Stanzi came in after Christensen threw a second-quarter interception, but Christensen bounced back in the second half, helping the Hawkeyes put the game out of reach.
Christensen was 9-of-15 for 122 yards, with one touchdown and one interception. Stanzi was 9-for-14 for 90 yards, playing most of the second quarter and re-entering the game in the fourth quarter.
Iowa's Bradley Fletcher came down with the interception off a tipped ball the first time Maine got the ball, and Christensen found Brandon Myers for a 4-yard touchdown pass to make it 14-0 with 3:37 to go the first quarter.
Christensen was 5-of-9 for 60 yards in the first half. But when he missed, he missed badly -- including an underthrow to Paul Chaney Jr. that Maine picked off at its own 3.
A.J. Edds bailed out Christensen with a safety that made it 16-0 with 12:31 to go in the second quarter, but Stanzi got the call for the rest of the half. He led the Hawkeyes to a pair of field goals to push Iowa's lead to 22-0.
Maine's Bryan Harvey hit a 40-yard field goal as half ended for the Black Bears' only points.
Adam Farkes was 9-of-22 for 83 yards and two interceptions for Maine.
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A months-old Facebook post has cost the Nebraska football stadium announcer his job one day after his hiring was announced.
Former running back Lawrence Phillips has been charged with first-degree murder in the April death of his cellmate at Kern Valley State Prison.
Michigan coach Jim Harbaugh said Tuesday he has informed competing quarterbacks Jake Rudock and Shane Morris of his decision on a starter for the Wolverines' opener Thursday night at Utah.
Michigan State quarterback and Heisman Trophy hopeful Connor Cook said he was disappointed his teammates didn't vote him among the team's three captains this season.
Former Oklahoma State return man and running back Ty Hill, who was dismissed from OSU's program after his arrest on domestic violence charges, has enrolled at West Alabama.
UCLA junior cornerback Ishmael Adams has been suspended indefinitely following a robbery arrest early Sunday morning, coach Jim Mora said Tuesday.