With star quarterback Trevor Lawrence isolated at home because of COVID-19, the top-ranked Clemson Tigers needed a double-digit second-half rally to beat the Boston College Eagles 34-28 on Saturday.

They did it behind freshman quarterback D.J. Uiagalelei, making his first career start in place of Lawrence, and two-time ACC Player of the Year Travis Etienne. The duo took over the game in the second half to erase an 18-point first-half deficit and complete the largest home comeback in school history.

Clemson did not find out until Thursday afternoon that Lawrence would be out after testing positive for the coronavirus. At that point, the game plan had already been set, and practice later that day would just be polishing up the details. Offensive coordinator Tony Elliott did not change the plan with Uiagalelei as the starter, believing his freshman could get the job done

After all, the Clemson coaching staff saw Uiagalelei come on campus as an early enrollee in January with a confidence about him, and knew the moment would not be too big for him. When head coach Dabo Swinney went to deliver the news that Uiagalelei would start, he found the quarterback studying game tape.

"He made some big, big plays, but what I loved the most about D.J. was his poise and his demeanor," Swinney said.

Uiagalelei calmly shrugged off his efforts in the large comeback.

"I've been down before in high school, playing in big games," he said. "Being down 18, that's not a lot of points. We have a great team. I knew we were going to come back. As long as we came out in the second half and executed, we were going to have a chance to win the ballgame. We all had complete confidence in ourselves that we knew what we had to do."

Uiagalelei went 30-of-41 for 342 yards with two touchdowns, while Etienne, a senior, set the ACC career rushing record and had a career-high 264 all-purpose yards with two touchdowns to help the Tigers stay undefeated. Clemson has now won 36 consecutive regular-season games, passing Boise State (35, 2008-10) for the longest such streak dating back to 2005.

"Everybody was worried about who's not here, but we were worried about who was here in the locker room," Etienne said.

Uiagalelei got the rally going, leading Clemson (7-0, 6-0 ACC) on three straight touchdown drives to start the second half. His 30-yard touchdown run opened the scoring in the second half. On the next possession, he threw an 8-yard touchdown pass to Amari Rodgers to narrow the gap to 28-26. Etienne, who also set the NCAA record for most games with a touchdown (42), put the Tigers ahead with a 17-yard touchdown run early in the fourth quarter.

"Nobody flinched, nobody panicked, there was never a doubt whether we were going to win the game," Swinney said. "I love that about our guys. That's what I told them. I said we've got a chance to show everybody what we're made of."

Boston College had several opportunities to take the lead in the fourth quarter but came up short. With 1:18 left in the game and Boston College deep in its own territory, quarterback Phil Jurkovec was called for intentional grounding in the end zone, resulting in a safety. In all, Clemson scored 24 unanswered points and shut out the Eagles in the second half.

The first half, however, could not have gone any differently for the Tigers. Boston College jumped out early behind Jurkovec and a rejuvenated passing game, as the QB threw two first-half touchdowns. The Eagles also took advantage of a major Clemson mistake on the goal line, when Etienne mishandled the handoff from Uiagalelei. Brandon Sebastian returned the fumble 97 yards for a score, and the Eagles led 28-13 at halftime.

Clemson really missed defensive starters James Skalski, Mike Jones and Tyler Davis, all out due to injury. Boston College also took advantage of some weaknesses that Clemson has been able to mask in the early part of the season -- including its pass defense and run game. Clemson simply could not run the ball in the first half, but that all changed behind Etienne when the rally began.

The Tigers' defense made some major adjustments in the second half. Boston College (4-3, 3-3) managed just 66 yards and went 0-for-5 on third down after halftime, and Jurkovec went 2-of-7 for 29 yards on passes 10-plus yards down the field.

"The bad part is you're down so many points you have a chance to have the greatest comeback," Swinney said. "That's not good. But to actually get it done, it's incredible. It's what it's all about. It's inspiring, and it shows you what our team is made of, it shows you how much they care, how much they believe. It's a four-quarter game. You keep playing, don't quit. We had a lot of adversity. It can destroy you, it can define you, but it can develop you, and I saw it develop our team today."

Swinney also announced Lawrence would miss next week's game at No. 4 Notre Dame, so Uiagalelei will start again. His performance on Saturday should do nothing but help his confidence moving forward.

There might be some bigger questions on defense, as defensive end Xavier Thomas will miss the first half against the Fighting Irish after being ejected for targeting in the first quarter. Skalski also might not be available after undergoing surgery on his groin, while the status of Davis and Jones will be updated later in the coming week.

But after the comeback victory, the stakes in the game against the Irish remain as high as they were when the season began.