PROVO, Utah -- BYU scored off enough of Colorado State's mistakes early that it didn't matter much when the 19th-ranked Cougars started making some gaffes of their own.
The Cougars converted two interceptions and a blocked punt into touchdowns in the first quarter, then held on in the second half for a 42-23 victory over the Rams on Saturday.
One week after being blown out at home by Florida State, BYU survived despite some sloppy moments.
"I thought it was a good win," said Max Hall, who passed for two touchdowns and ran for another. "We had some ups and some downs, but for the most part I thought the guys played hard."
Hall finished 18-for-29 for 241 yards, two touchdowns and two interceptions, and Harvey Unga ran for three touchdowns and became the Cougars' first 100-yard rusher with 113 yards on 22 carries.
The Cougars (3-1, 1-0 Mountain West) had to overcome 10 penalties and a surge by the Rams (3-1, 0-1) in the second half.
Grant Stucker completed 30 of 50 passes for 372 yards and two touchdowns for the Rams, whose six-game winning streak ended.
Colorado State gained 438 yards on the Cougars, but it was still an improvement on BYU's performance in a 54-28 loss to Florida State the previous week.
"Yards to me aren't the indicator. It's points," BYU coach Bronco Mendenhall said. "Any time that we hold an opponent to 24 points or under, we win a lot of football games."
Tyson Liggett had 11 catches for 156 yards and a touchdown for the Rams, who never recovered after the first quarter.
"You just can't do the things we did on offense and special teams in the first quarter and expect to be in the game," coach Steve Fairchild said. "I think we are a better team than what we showed in the first quarter, but once we went down that road I knew it was going to be a long afternoon."
The Rams lost their sixth straight to BYU.
Colorado State got within 28-17 on a field goal early in the fourth quarter and answered Unga's third TD run with a 13-yard touchdown pass from Stucker to Liggett to make it 35-23 after the two-point conversion failed. But the Rams could not keep matching BYU to overcome the deficit.
Hall added a 24-yard touchdown pass to Spencer Hafoka less than a minute later to finally finish off the Rams.
The Cougars led 21-0 after the first quarter, needing only a pair of plays on each drive to cover the short distances to the goal.
"Any time the defense does a great job of returning the ball back to us, it's on us to capitalize on that," said Unga, who ran for 88 yards in the second half. "I felt like we came out strong and that caught Colorado State in a little bit of a bind."
Colorado State receiver Rashaun Greer tipped both intercepted passes high enough that a defender was easily able to grab it. Brian Logan had the first, leading to Unga's 4-yard touchdown run barely two minutes into the game, then Andrew Rich grabbed the second at the Colorado State 39.
Hall threw a 37-yard pass to O'Neill Chambers down the sideline, then Hall faked out everybody with a bootleg and trotted into the end zone with 3:04 left.
The Cougars got the ball right back when Matt Marshall blocked a punt and BYU went up 21-0 on Unga's 5-yard run with 25 seconds left in the first.
"They gave us a couple of gifts," defensive end Jan Jorgensen said. "But we always appreciate those gifts and it's nice to be able to get off the field quick."
Hall's pass to McKay Jacobson for an apparent touchdown was overturned for pass interference called on Dennis Pitta. It was one of 10 BYU penalties called in the game, but Pitta redeemed himself on the next play with a diving catch on an 18-yard touchdown pass from Hall to put BYU up 28-7.
"I guess I took that one away from McKay," Pitta joked. It worked out well for me. McKay wasn't too happy about it."