TCF Bank Stadium was so full Thursday night, the students seemed to be standing atop one another. There were no empty seats or benches, and fans were stacked multiple rows deep atop the upper deck in standing room only.

With the 80-degree heat, and the smell of a potential upset in the air, the six-year-old brick house was a cauldron of screams, songs and sweat.

TCU never trailed, but the second-ranked Horned Frogs never looked comfortable either. In that sense, the unranked Gophers accomplished something, even as No. 2 TCU finished off a 23-17 season-opening victory.

An announced crowd of 54,147 — the largest in the stadium’s history — watched as Trevone Boykin showed why he’s a Heisman Trophy candidate, doing just enough with his arm and legs to stifle Minnesota’s upset bid.

Mitch Leidner’s 22-yard touchdown pass to KJ Maye trimmed TCU’s lead to six points with 90 seconds remaining, but the Horned Frogs recovered the subsequent onside kick.

TCU outgained the Gophers 449-341, but the main difference was Boykin — and two crushing first-half fumbles by the Gophers.

Boykin completed 26 of 42 passes for 246 yards and a touchdown, and added 92 yards and another TD rushing.

Gophers quarterback Mitch Leidner couldn’t match that. He completed 19 of 35 passes for 197 yards and added only 23 yards on the ground.

“We threw the ball well at times,” Gophers coach Jerry Kill said. “What hurt us were some [offensive line] protection situations. It had nothing to do with Mitch. He got hit in the back a couple times.”

The Gophers clearly missed tight end Maxx Williams, as Nate Wozniak and Brandon Lingen had one catch apiece — the only receptions by Minnesota tight ends. And they missed another now employed in the NFL, running back David Cobb, though redshirt freshman Rodney Smith did a fair impersonation with 16 carries for 88 yards and a touchdown.

“Sometimes things don’t go the way you want them to,” Leidner said. “But I think overall, as an offensive unit, if we clean up some things, we’re going to be great offensively.”

At halftime, TCU was clinging to a 10-3 lead, and the Gophers knew that score could have been reversed if not for two costly turnovers.

Jaden Oberkrom hit a 53-yard field goal on TCU’s first drive, and then defensive end Terrell Lathan got around left tackle Ben Lauer to sack Leidner, popping the ball loose.

TCU recovered at Minnesota’s 15-yard line, and moments later, Boykin hit Josh Doctson for a 9-yard touchdown. Just like that, TCU led 10-0.

But the Gophers defense stiffened, and the offense started to find its footing. They ran the flea-flicker, with Leidner hitting Maye for a 36-yard gain. Four plays later, Rodrick Williams went airborne for a 6-yard gain but fumbled the ball at the 1, with the ball bouncing through the end zone for a touchback.

“I said all week, it comes down to turnovers,” Kill said. “Those were two huge plays in the football game.”

Last year, the Gophers made five turnovers in their 30-7 loss at TCU, including four by a hobbled Leidner. They vowed to make things different, but the Horned Frogs have long specialized in takeaways under coach Gary Patterson.

The Horned Frogs took the second-half kickoff and went 76 yards for a touchdown, capped by Boykin’s 19-yard run. He ran to the sideline and made a great cut, slipping through multiple defenders for the score.

But on TCU’s next drive, the Gophers forced Boykin into an interception. Alex Keith brought pressure and might have altered Boykin’s throwing motion. The errant pass sailed right to Gophers cornerback Eric Murray.

The Gophers marched 73 yards to turn that into seven points. Drew Wolitarsky caught a pass from Leidner and turned that into a 30-yard gain. Then Smith took over with runs of 15 and seven yards before capping the drive with a 1-yard touchdown.

But Oberkrom added field goals of 45 and 33 yards, and the Gophers didn’t score again until Leidner hit Maye with a touchdown pass late in the fourth quarter.

The Gophers fell to 1-10 in games against teams from the AP top five since 1990, with their last victory in that category coming when they defeated No. 2 Penn State 24-23 in 1999.

This loss puts the Gophers in a tough spot heading into their Week 2 game at Colorado State on Sept. 12. The Rams were 6-0 last season playing in the 5,000-feet altitude in Fort Collins.