GAINESVILLE, Fla. (AP) -- The second Jeff Driskel started waving for help, Florida coach Will Muschamp knew it was bad.
It turned out to be the worst-case scenario.
Driskel broke his lower right leg Saturday in the first quarter of the 19th-ranked Gators' 31-17 victory over Tennessee, a season-ending injury that thrust seldom-used backup Tyler Murphy onto the field for the most significant action of his four-year career.
Murphy responded better than anyone could have realistically expected.
He had a 52-yard touchdown throw to Solomon Patton, a swing pass that went the distance, and made several huge plays with his legs as Florida (2-1, 1-0 SEC) won its ninth consecutive game in the series.
Driskel, who was playing with a brace on his sprained left knee, broke his right leg while throwing an interception in the first quarter. Devaun Swafford picked off the pass and returned it 62 yards for a touchdown and a 7-0 lead. Marlon Walls pulled Driskel to the ground and landed on his leg as he released the ball.
Driskel tried to get up, but then dropped back to the turf and called for trainers. He limped off the field a few minutes later, got checked on the sideline and then used crutches to get to the locker room.
''I hurt for him and I hurt for us right now,'' Muschamp said. ''It's going to hurt us. He's a guy that's won a lot of ballgames here, and it's disappointing for him right now.''
It was a solid debut for Murphy, a junior whose only pass attempt came on a 2-point attempt two weeks ago.
''It was always in the back of my mind that I might never play,'' Murphy said. ''I just kept working hard and kept fighting and kept faith in myself and kept praying for an opportunity. It wasn't the way I wanted it, but an opportunity is an opportunity.''
Murphy's 7-yard TD scamper in the fourth quarter made it 31-10 and sent fans scrambling for the exits.
The Volunteers (2-2, 0-1) had hoped to rebound from an embarrassing, 59-14 loss at No. 2 Oregon a week ago. Instead, Tennessee and first-year coach Butch Jones left Gainesville with another double-digit setback.
Jones' strangest decision might have been to bench Justin Worley and give redshirt freshman Nathan Peterman his first career start on the road and in front of 90,000.
Peterman, who grew up in nearby Jacksonville, had three turnovers in a 17-minute span in the first half and was benched at the break. He completed 4 of 11 passes for 5 yards, with two interceptions and a fumble.
''To beat a team at home, you can't turn the football over,'' Jones said. ''Way too many turnovers.''
Worley wasn't a whole lot better against a Florida defense which has been mostly dominant through three games.
Worley, who started the first three games, finished 10 of 23 for 149 yards, with a touchdown and two interceptions.
''Losing is never accepted or tolerated at Tennessee,'' Jones said. ''But I'm proud of our team. They showed resiliency. They didn't quit. They gave us an opportunity to be in the game at the end of the game. We have to keep getting better. We have to keep things in perspective as we continue to build this football program. We took some small steps, but we have a long way to go.''
Where Florida goes from here will largely depend on Murphy.
He completed 8 of 14 passes for 134 yards. He ran 10 times for 84 yards.
''He didn't just manage our team,'' Muschamp said. ''He produced in critical situations.''
Murphy made a few mistakes, but only one costly one. He wasn't looking and took a snap off his facemask, a botched play that resulted in a fumble.
That was one of nine turnovers on the day.
The Volunteers had six - four in the first half. Peterman had three, and Raijon Neal fumbled on the team's second play. Dante Fowler Jr. wrecked the exchange, his first of several big plays.
Florida had three turnovers in the first half, including running back Matt Jones' second in two games. Jones was benched in favor of Mack Brown, who ran 24 times for 86 yards and a touchdown. Muschamp said he's going to go with the ''hot hand'' at running back beginning next week at Kentucky.
This much is certain: Murphy will be under center.
Murphy has been buried on the depth chart, watching from the sideline as Driskel, Jacoby Brissett, John Brantley, Jordan Reed and Trey Burton all took snaps ahead of him the last three years.
He considered transferring, but refused to listen to all the people urging him to change positions.
''I just didn't want to give up,'' Murphy said. ''I felt like if I changed positions, I would have gave up on myself and I probably wouldn't be able to live with myself.''