UNIVERSITY PARK, Pa. -- Penn State still can't figure out a way to beat Iowa.

The unranked Hawkeyes (4-0) scored 21 unanswered points last night en route to a 21-10 victory against No. 5 Penn State in the Big Ten Conference opener for both teams at Beaver Stadium.

The Nittany Lions (3-1) had four turnovers, including three in the fourth quarter. They also had a blocked punt returned for a touchdown and surrendered a safety, as Iowa coach Kirk Ferentz continued his mastery over Joe Paterno.

"It was a team loss," said Paterno, whose record dropped to 2-7 against Ferentz. "No one person or no one play lost it. We got licked."

Against the Hawkeyes, quarterback Daryll Clark started 6 of 8 for 104 yards and a touchdown -- a 79-yard pass to wide receiver Chaz Powell on the Lions' first play from scrimmage.

But he was only 6 of 24 for 94 yards the rest of the way with three interceptions, two of which came in the fourth quarter, and two sacks. He also fumbled in the end zone for a safety after being hit by Iowa's Broderick Binns.

In the past two games against Iowa, Clark is 21 of 55 (38.2 percent) for 284 yards and one touchdown. He has thrown four interceptions, including one that set up the winning field goal a year ago in Iowa City.

Hard as it is to believe, Anthony Morelli is the only Penn State quarterback to beat Iowa this decade. The Hawkeyes have won seven of the past eight meetings.

"What we do after this will determine what type of team we have," Clark said. "There's a lot of ball left. We had a couple of dropped passes, a couple of tipped balls, a couple of misreads by myself. It just added up."

Iowa, which trailed 10-0 after one quarter, recorded its first points came on a safety in the second quarter. Binns beat Penn State right tackle DeOn'tae Pannell and hit Clark, who fumbled. Lions left guard Johnnie Troutman recovered the loose ball in the end zone, but the Hawkeyes were credited with a safety.

Iowa kicker Daniel Murray, the hero of the upset victory a year ago, kicked his first of three field goals -- a 41-yarder in the second quarter -- as the Hawkeyes pulled to within 10-5 at halftime.

Iowa did most of its damage in the fourth quarter, scoring 16 points against the Lions, who fell to 2-8 in Big Ten openers since 2000.

Adrian Clayborn scampered past inside up back Nick Sukay to block Jeremy Boone's punt. Clayborn scooped up the loose ball and returned it 53 yards, giving the Hawkeyes their first lead at 11-10. Boone, the Big Ten's leading punter the past two seasons, had never had a kick blocked.

"There was a mistake in blocking," Paterno said.

Clark tossed his second interception on the next series, which set up Adam Robinson's 13-yard run with 8:32 remaining, giving the Hawkeyes an 18-10 lead.

Penn State tailback Evan Royster fumbled on the next series and Clark threw another interception a short time later. The Lions finished with a season-low 307 yards of offense and just 109 on the ground.

"Maybe we're a little more humble now, and a little more hungry," said outside linebacker Navorro Bowman, who returned to the lineup after missing the past two games with a sore groin. He tied middle linebacker Josh Hull for the team lead in tackles with 13.

Penn State's defense allowed just 298 yards of offense and intercepted quarterback Ricky Stanzi twice. One of the turnovers, an interception by Sukay, led to Collin Wagner's 27-yard field goal with 52 seconds to go in the first quarter.

The Lions were blanked the rest of the way.

NOTES -- Outside linebacker Sean Lee (Upper St. Clair) dressed for the game, but did not play. He had a brace on his sprained left knee. Bani Gbadyu started in Lee's absence. ... Powell led the Lions with three catches for 96 yards. ... Royster had 69 yards on 17 carries. ... Backup cornerback A.J. Wallace had an interception. ... Sukay (Greensburg Central Catholic) had a career-high nine tackles and broke up four passes. ... Hull had a sack while defensive end Jack Crawford and cornerback D'Anton Lynn shared another. ... The safety was the first yielded by Penn State since Nov. 13, 2004 at Indiana. ... Penn State is at Illinois Saturday.

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