LUBBOCK, Texas -- Texas Tech notched an upset victory over 24th-ranked TCU and perhaps gained a quarterback controversy to go with it.
Walk-on quarterback Baker Mayfield, who was phenomenal in the Red Raiders' first two games, left with a fourth-quarter injury, and backup Davis Webb entered to spark the Red Raiders to a 20-10 win Thursday night at AT&T Jones Stadium.
TCU erased a 10-0 deficit, tying the game midway through the fourth quarter and taking the game's momentum.
Mayfield threw incomplete or was intercepted on nine consecutive passes in the second half. He then threw for a 1-yard loss to running back DeAndre Washington and came up favoring his right leg.
Webb took over and led the Red Raiders for 76 yards in eight plays for the go-ahead score. Webb's 19-yard touchdown pass to Bradley Marquez with 3:48 remaining in the fourth quarter gave Texas Tech a 17-10 lead.
"We needed a quarterback to go in and make plays," Texas Tech's first-year coach Kliff Kingsbury said. "That's what he did. He kept himself ready and was there when we needed him."
After TCU went three-and-out on its ensuing possession, Texas Tech drove for a Ryan Bustin 37-yard field goal with 2:43 left.
Texas Tech (3-0, 1-0 Big 12) finally came through on offense in the fourth quarter, supplementing the team's outstanding defensive effort. Though TCU finished with more first downs (23-16) and total yards (401-336), the Red Raiders made the key defensive plays despite a sputtering offense.
"It was a bizarre game, but I thought our effort was incredible," Kingsbury said. "It was the best defensive performance I've been a part of since I've been a coach."
Meanwhile, TCU coach Gary Patterson was disturbed by the number of penalties his team drew. The Horned Frogs were flagged 13 times for 115 yards.
"I can't talk about the officiating," Patterson said. "I'm not happy. We can't have as many penalties as we had. It can't happen."
Early in the fourth quarter, TCU (1-2, 0-1 Big 12) put together its best drive of the game. Horned Frogs quarterback Trevone Boykin completed a 22-yard pass to Cam White on third-and-8 to keep the drive going. From there, TCU kept the ball on the ground and rolled over the Red Raiders.
Running back B.J. Catalon capped the 69-yard drive with a 17-yard touchdown run, tying the game at 10 with 6:28 left.
Texas Tech appeared to answer when Webb threw a 49-yard touchdown pass to Washington. However, a replay revealed Washington dropped the ball at the half-yard line. After two penalties backed up the Red Raiders, Webb ultimately hit Marquez for the deciding score.
"I was able to get a bead on my guy and keep him on my back shoulder," Marquez said.
Marquez said Webb's attitude lifted the team.
"He was prepared for the situation, and it's a credit to his preparation," Marquez said. "He was definitely a spark for all of us. We were able to control the game from that point."
Webb completed three of four passes for 77 yards. Texas Tech tight end Jace Amaro produced game highs with nine receptions for 97 yards.
"We knew the backup was good," TCU safety Sam Carter said. "But before that, we were good."
Mayfield produced 216 yards on 21-of-40 passing. He threw one touchdown pass and was intercepted three times.
Boykin went 23-for-36 for 194 yards and two interceptions. He also ran 20 times for 101 yards.
Texas Tech dominated the first half but went to halftime with only a 10-0 lead due to turnovers and penalties on TCU's side of the 50-yard line.
The Red Raiders scored on the game's first possession. Mayfield led a six-play, 75-yard scoring drive that culminated in running back Kenny Williams' 50-yard touchdown reception.
Williams caught the pass at the line of scrimmage, broke a tackle and left the Horned Frogs behind him, giving Texas Tech a 7-0 lead just 69 seconds into the game.
The Red Raiders pushed the lead to 10 points on Bustin's 39-yard field goal late in the first quarter.
The Red Raiders outgained the Horned Frogs 211 yards to 133 in the first half, but Mayfield threw two interceptions, both in TCU territory, to keep Texas Tech from extending its lead.
TCU safety Chris Hackett intercepted Mayfield's pass at the Horned Frogs' 17 to end Texas Tech's second offensive series. In the second quarter, TCU cornerback Kevin White grabbed the ball away from Marquez at the Horned Frogs' 42.
Texas Tech also had a drive inside the TCU 20 foiled by penalties. Mayfield ran for 16 yards to the TCU 17 on a third-and-7 play, but the run was called back for a holding penalty, and the Red Raiders couldn't move back inside the TCU 40.
Meanwhile, TCU managed only six first downs in the first half and never crossed the Texas Tech 40.
NOTES: Texas Tech wore gray jerseys and gray helmets for the first time in school history. ... Texas Tech hosted a Thursday night game for the first time since 1994, when the Red Raiders lost to top-ranked Nebraska 42-16. ... TCU won its first-ever Big 12 opener last season, 20-6 at Kansas. ... The Horned Frogs entered the contest having won 16 of 17 conference road games.