BLOOMINGTON, Ind. — Ohio State knew it wasn’t going to be a cakewalk opening the season at Indiana.

The Hoosiers had billed Thursday night’s game as its biggest home opener ever, and Indiana has given Ohio State fits in recent years, even if it hadn’t beaten the Buckeyes since 1988.

Sure enough, for much of the night it was an uphill battle, but No. 2-ranked Ohio State asserted itself in the second half for a 49-21 victory at sold-out Memorial Stadium.

After Ohio State trailed 14-13 at halftime and 21-20 with five minutes left in the third quarter, the Buckeyes’ dormant passing game finally awoke. J.T. Barrett threw touchdown passes to Parris Campbell, Johnnie Dixon and Binjimen Victor to allow the Buckeyes to exhale. Barrett finished with 304 yards on 20-of-35 passing. It was his first 300-yard passing game since the 2016 opener against Bowling Green.

It helped that Ohio State’s defense, torched until then by IU quarterback Richard Lagow, asserted itself. Lagow threw for 410 yards, but only 55 after he threw a 2-yard touchdown pass to Ian Thomas to give the Hoosiers their last lead late in the third quarter.

Once Ohio State clamped down on Indiana’s passing game, the Hoosiers had no recourse. They gained only 17 yards in 27 runs.

Balance wasn’t a problem for the Buckeyes, thanks to an impressive debut by true freshman running back J.K. Dobbins. Mike Weber didn’t play — coach Urban Meyer said he sustained a “tug” on a lingering hamstring issue in practice this week — and Dobbins proved the training-camp hype about him was justified.

Showing vision, lateral quickness and strength, Dobbins ran for 181 yards on 29 carries.

“I’m not surprised at all,” Meyer said. “We’ve seen that since spring practice. Mike Weber could have gone. He was about 80 percent. When he gets back, we’ll have a nice 1-2 punch.”

Asked who would start next week against Oklahoma, Meyer smiled.

“J.K. Weber,” he quipped.

The running game, whoever carried the ball, figured to be solid this year. It was the passing game that was the big question mark about the Buckeyes, and doubts persisted until the third-quarter ignition. Campbell, for example, dropped a would-be touchdown pass earlier in the quarter.

He got redemption quickly. The junior caught a ball on a crossing pattern, got a key block from Terry McLaurin and outran pursuers for a 74-yard touchdown.

After a three-and-out by Ohio State’s defense, Dixon, who’d dropped the first pass thrown to him, snagged a dart by Barrett and ran for a 59-yard score to pad the lead to 35-21.

Defensive tackle Jashon Cornell stripped the ball from Lagow on IU’s next series, and Barrett threw to Victor for an 11-yard score to end any suspense about the outcome.

“I thought we operated in the second half faster,” Barrett said. “Defensive guys weren’t able to get set.”

The second-half explosion was a major contrast to the first half. The game started well enough for the Buckeyes. Barrett completed his first four passes for 55 yards on the game’s first possession before Ohio State had to settle for a Sean Nuernberger field goal.

But the Buckeyes’ offense then went into a prolonged funk. Ohio State gained only one first down in its next four possessions.

The Buckeyes’ defense, meanwhile, struggled to slow Indiana’s offense. Lagow, aided by several talented veteran receivers, picked apart a secondary that is replacing three first-round NFL picks. Lagow threw a 18-yard pass to Thomas to give IU a 7-3 lead on its first possession. The Hoosiers later drove 80 yards for a touchdown that made it 14-6.

For the half, Indiana outgained Ohio State 286-216, with all but two of IU’s yards coming through the air. After the quick start, Barrett completed only 6 of 17 for 40 yards the rest of the first half.

“Yeah, I was (upset),” Meyer said about halftime. “They understood they didn’t play very well. But there was no panic.”

The Buckeyes answered this challenge, but a bigger one awaits next week against an Oklahoma team hungry for redemption after Ohio State’s win in Norman last year.

“This was a very good test, especially with what’s coming down the pike next week,” Meyer said. “But we’ve never not had great respect for Indiana. We expected it to be a tough game.”