AMES, Iowa » Third-ranked TCU has made it through the toughest stretch of the season with its playoff hopes intact.

Now the Horned Frogs have a week to rest up before their final push for the Big 12 title and beyond.

Trevone Boykin threw for 436 yards and four touchdowns and TCU rolled past Iowa State 45-21 Saturday night for its third road win in four weeks.

Josh Doctson had 190 yards receiving and two TDs for the Horned Frogs (7-0, 4-0 Big 12), who went on a 31-0 run after the first quarter.

Boykin’s 3-yard TD run with 14:36 left put TCU ahead 38-21. Doctson made it a rout with a 42-yard touchdown catch six minutes later.

Sam Richardson had 251 yards passing for Iowa State (2-4, 1-2).

For a quarter, the Cyclones did what they could to pull off what would have been a huge upset, taking a 21-14 lead in the first.

TCU dashed their dreams with a pair of long drives and a suddenly stout defense.

The Horned Frogs went 86 yards to open the second half, and a 13-yard TD run by Kyle Hicks made it 31-21. Nick Orr forced a fumble on a blind side blitz to kill an Iowa State drive, and Boykin’s touchdown run capped an 85-yard drive that put Iowa State behind by 17.

The Cyclones were threatening to pull back within 10, but Joshua Thomas fell down on a fourth-down screen pass with 11:20 to go.

Freshman Mike Warren had just 78 yards rushing for Iowa State. Warren had averaged 182 yards over his three previous starts.

Iowa State coach Paul Rhoads had preached to his team all week about the importance of a fast start.

The Cyclones got one, with a 74-yard touchdown reception by Allen Lazard — who finished with 147 yards on five catches — bookended by short TD runs by Thomas and Warren in the first quarter.

TCU started just as quickly though, scoring on TD throws from Boykin to Doctson (20 yards), Kolby Listenbee (21 yards) and Charlie Reid (14 yards).

The Horned Frogs took a 24-21 halftime lead on a 23-yard field goal.

TCU safety Denzel Johnson was ejected in the second quarter for targeting.

It wasn’t surprising to see the Horned Frogs let the Cyclones hang around after close road wins over Minnesota, Texas Tech and K-State.

But after allowing 262 yards in the first quarter, TCU allowed just 199 the rest of the way.

The Horned Frogs, who’ve battled injuries all year, lost wide receiver KaVontae Turpin with an apparent upper-body injury.

They’ll be able to sit Turpin and everyone else for at least a few days before returning to host reeling West Virginia on Oct. 29.