COLUMBUS, Ohio -- Carlos Hyde scored on a highlight-reel touchdown run early in the fourth quarter and No. 4 Ohio State survived a scare and the ejection of senior cornerback Bradley Roby to beat Iowa, 34-24, on Saturday at Ohio Stadium.
Roby's replacement, Armani Reeves, was twice beaten on touchdown passes, including an 85-yarder from Jake Rudock to tight end Jake Duzey down the right sideline with 2:30 left in the third quarter to tie score, 24-24.
"Roby's a big part of our defense and our team too," Reeves said. "Losing a guy like that, you've got find a way to bounce back. As team we had to come together."
Ohio State (7-0 overall, 3-0 in the Big Ten) went ahead, 31-24, with 13:24 to play on a staggering 19-yard touchdown run by Hyde.
Hyde broke through the line, was hit at the eight-yard-line by Tanner Miller and stumbled back to the 11, but regained his balance before diving over the goal line at the right pylon.
"I've never had a run like that, but that play was working all day," Hyde said of the play called 13-dash. "I told (running backs coach Stan) Drayton we need to do a little more of it.
"The safety come up and hit me. I came out of it and I was still up. I was like, 'Let me try to catch my balance.' Once I did, I turned around and seen Philly Brown with an unbelievable block. I was like, 'Man, I haven't even scored yet,' when I seen that block and just went in for the touchdown."
Ohio State added a 25-yard field goal by Drew Basil with 5:21 left for the final margin.
"You don't get prizes for playing a good first half," Iowa coach Kirk Ferentz said. "You have to play the full 60 minutes. I think we realize it's a matter of what do we have to do to be in a better situation the next time we get this chance."
Ohio State scored twice in the third quarter to turn a 17-10 deficit into a 24-17 lead.
The Buckeyes got the kickoff and drove 75 yards, culminating in a one-yard touchdown run by Hyde to make it 17-17. Iowa had been the only FBS team not to have allowed a running touchdown this season, and it came on the 205th carry of the season by the opposition.
Braxton Miller followed with a 14-yard pass-and-run to Devin Smith for the touchdown that put Ohio State ahead.
Iowa (4-3, 1-2), whose previous three scoring drives all reached double figures in plays, needed only one play, to Duzey, to set up a tense final quarter.
"Defensively, very disappointed in the first half," Ohio State coach Urban Meyer said. "(I) felt we were getting pushed around. And I thought in the second half they did a much better job, much better job. "But once again you've got to give them credit. That's a good outfit we beat and a tough physical game. So the best thing about 7-0 is the chance to go 8-0."
Ohio State lost its first player to the new "targeting" rule when Roby, a preseason All-American, was ejected with 1:15 left in the first quarter.
Roby launched himself at C.J. Fiedorowicz after an 11-yard gain across the middle. Roby, a 2012 All-Big Ten selection, led with his shoulder but his helmet caught Fiedorowicz in the neck area. The call on the field was reviewed and upheld.
With Roby gone, the Buckeyes were without their usual starting cornerbacks. Christian Bryant sustained a broken ankle Sept. 28 against Wisconsin.
"It's hard; that's an emotional thing," Ohio State defensive coordinator Luke Fickell said of losing Roby. "It really hurt us most in our third-down package.
"That first half, we were really limited. He's the basis for a lot of the things we do on the boundary side. It put us in a little bit of a bind. We had to regroup and gather ourselves."
The 15-yard penalty on Roby gave the Hawkeyes a first down at Ohio State's 13-yard line, but Iowa had to settle for a 28-yard field goal by Mike Meyer and a 10-3 lead after the first quarter.
Miller hit Philly Brown on a 58-yard touchdown pass early in the second quarter to tie it, 10-10.
Rudock's six-yard touchdown pass to Kevonte Martin-Manley put Iowa up, 17-10, at halftime.
"It was a good game," Iowa running back Mark Weisman said. "We played tough out there. We battled out there and made improvements. Obviously we are never satisfied without a win."
NOTES: Ohio State has won 19 consecutive games, all under coach Urban Meyer, to tie the second-longest winning streak in program history, trailing only the 22 wins from 1967 to 1969. ... The Hawkeyes played in Columbus for the first time since losing, 27-24, in overtime on Nov. 14, 2009, in a game that decided the Big Ten championship. ... The Hawkeyes have lost five straight in the series since a 33-7 home victory on Oct. 16, 2004, and trail in the series, 47-14-3.