It was Clay's eighth consecutive 100-yard rushing game as the Badgers won their 15th home opener in a row and improved to 13-0 in nonconference regular-season games under coach Bret Bielema.
Gilreath took a hard hit near the head during the third quarter and was down on the field for nearly 10 minutes. He was eventually taken away in an ambulance. He had a concussion.
NO. 4 TEXAS CHRISTIAN 62, TENNESSEE TECH 7
In Fort Worth, Texas, Matthew Tucker ran for two touchdowns, Andy Dalton threw for a score and the Horned Frogs stretched their home winning streak to 15 games with a victory over Tennessee Tech from the FCS.
Dalton completed 15 of 21 passes for 182 yards.
NO. 5 TEXAS 34, WYOMING 7
In Austin, Texas, Garrett Gilbert passed for 222 yards and a touchdown and Texas shook off another slow start to beat Wyoming.
Gilbert was 22 of 35 with a 45-yard touchdown to receiver Mike Davis in the second quarter.
NO. 6 NEBRASKA 38, IDAHO 17
In Lincoln, Neb., Taylor Martinez ran for 157 yards and two touchdowns and Nebraska's defense intercepted Nathan Enderle five times and had seven sacks as the Cornhuskers defeated Idaho.
DeJon Gomes and Rickey Thenarse each ran back interceptions for touchdowns for the Huskers.
Martinez went over 100 yards rushing for the second straight game and Roy Helu Jr. added 107 yards and a touchdown on the ground for Nebraska.
Enderle was sacked five times and threw three of his five interceptions on consecutive possessions in the second quarter. Nebraska converted each of those second-quarter picks into touchdowns to go up 31-3 at half.
NO. 9 IOWA 35, IOWA STATE 7
In Iowa City, Iowa, Adam Robinson rushed for a career-high 156 yards and a touchdown on 14 carries as Iowa crushed Iowa State for its third win in a row over the rival Cyclones.
Ricky Stanzi threw two touchdown passes and ran for another score for the Hawkeyes (2-0), who scored touchdowns on four of their first five drives.
Iowa State's Austen Arnaud threw three interceptions in the third quarter.
NO. 20 UTAH 38, UNLV 10
In Salt Lake City, Terrance Cain passed for two touchdowns in his first start in almost a year and Shaky Smithson returned a punt 77 yards for a score as Utah beat UNLV.
Eddie Wide ran for two touchdowns and the Utes won their 19th in a row at home and their final Mountain West Conference opener.