FORT WORTH, Texas -- The No. 15 TCU Horned Frogs, playing without suspended starting quarterback Casey Pachall, lost its nation's-best 12-game winning streak -- and quite possibly its national ranking -- as early big strikes from surprise Iowa State starting quarterback Jared Barnett sparked the Cyclones to a 37-23 victory.
The sophomore Barnett, listed as the second-string quarterback on the Cyclones' game-day depth chart, replaced struggling senior Steele Jantz and hooked up with Josh Lenz for a 51-yard touchdown pass barely a minute into the game and before connecting with Lenz on a 74-yard bomb with a minute to go in the first quarter.
Iowa State (4-1, 1-1 in Big 12), despite being outgained 455 yards to 350 and stagnating offensively for chunks at a time, rode its early lead and never trailed in the game Saturday in front of 42,152 at remodeled Amon G. Carter Stadium.
Transitioning TCU (4-1, 1-1), in its new conference and unexpectedly now with a new quarterback, suffered a massively disappointing first loss of the season in its first-ever Big 12 home game.
"They were manned-up and we knew we were going to take a shot at them early," said Lenz, who finished with five catches for 147 yards and also threw a 15-yard touchdown pass off a reverse early in the fourth quarter.
"We wanted to take advantage of the way their safeties play," Barnett said.
Playing without Pachall -- the nation's fifth-ranked quarterback in passing efficiency who was arrested early Thursday morning on suspicion of driving while intoxicated and then quickly suspended indefinitely by coach Gary Patterson -- as well as their top two tailbacks, the Horned Frogs' dual-threat redshirt freshman quarterback Trevone Boykin still put a scare into Paul Rhoads' improving Cyclones.
Boykin completed 23 of 40 passes for 270 yards, surpassing Pachall's per-game average, but he and a pair of untested running backs combined for five turnovers, three in the first half. Freshman running back B.J. Catalon fumbled on consecutive drives in the second quarter, the first coming at the Iowa State 3-yard line with TCU trailing 16-7.
Boykin threw three interceptions, tripling Pachall's season total. His second pick was a killer, snatched out of the air at the line of scrimmage by 280-pound Cyclones lineman David Irving and returned for a touchdown for a 37-23 lead midway through the fourth quarter. Boykin's third pick came at the Iowa state 2-yard line with 2:15 to go.
"You look at this one and you know how we got beat," Patterson said. "You can't give up big plays on defense and you can't give up the ball on offense. You have to give all the credit to Coach Rhoads and Iowa State. They came into our house, beat us fair and square and pushed us around."
It was just TCU's second loss in its last 30 home games.
"Losing is a disease. If you don't do something about it, it will just keep spreading," said Patterson, who has yet to determine how long Pachall will remain suspended. "I am not a very good loser. You have to give them a lot of credit."
After TCU opened the second half with a three-and-out, Barnett and Lenz connected for a third touchdown pass and a 23-10 lead, this one a one-yarder to cap an 80-yard drive bolstered by big holes for a ground game that had been silent in the first half.
The Frogs made it 23-17 and then 23-20, but consecutive personal-foul penalties by the defense early in the fourth quarter aided the Cyclones' final offensive touchdown that made it 30-20.
The difference was Barnett, and especially early with the big strikes. He started the game 7-of-8 and finished 12-of-21 for 183 yards, with three touchdowns and one interception.
"He did what Jared does well," Rhoads said, referencing to Barnett's week leading up to earning the starting job. "He operated with great composure, was in control and moved the team. I felt the team had confidence in that."
Iowa State beat a ranked opponent for the first time in three seasons and hopes to carry the momentum into next week's home game against Kansas State. Meanwhile, the suddenly reeling Frogs begin a treacherous stretch next Saturday at Baylor.
NOTES: TCU played without leading rusher Matthew Tucker (ankle). He was replaced by little-used senior Aundre Dean and freshman B.J. Catalon. Dean's seven-yard touchdown catch in the first quarter was the first TD catch of his career and first score since Nov. 27, 2010 ... Iowa State's 16 first-quarter points matched the highest point total TCU had allowed in a game this season ... Iowa State kicker Edward Arceo made a 46-yard field-goal attempt in the first quarter, his second field goal of at least 46 yards this season ... TCU freshman kicker Jaden Oberkrom hit a 50-yard attempt in the third quarter, the first 50-yarder by a TCU kicker since 2008.