NORMAN, Okla. (AP) - Paul Rhoads felt struggling Iowa State was playing well until one particular punt right before halftime.
Then everything fell apart in a hurry for the Cyclones.
Iowa State's promising start quickly became a fond memory after it surrendered a punt return for a touchdown, sending No. 22 Oklahoma to a 48-10 victory Saturday.
Jalen Saunders' 91-yard play with 1:09 remaining in the first half tied it at 10 and erased any momentum for the Cyclones (1-9, 0-7 Big 12). It was part of 45 unanswered points for the Sooners over the final three quarters.
''We had the guy surrounded a long way from the goal line, and then he escapes and makes a great play,'' Rhoads said. ''Woe is me. Why us? I can't believe this is happening again.''
Trevor Knight led the way as Bob Stoops recorded win No. 157 with Oklahoma, tying him with good friend Barry Switzer for the most coaching victories at the school.
''I've done my best to ignore that or stay away from it,'' Stoops said of tying Switzer's record. ''All I'll do is compliment coach Switzer. He was a special coach at his time. Not many coaches have a Super Bowl with three national championships.''
Knight, who replaced the injured Blake Bell in the second quarter, was 8-of-14 passing for 61 yards and rushed for 123 yards and one touchdown. Damien Williams added 10 carries for 128 yards and two touchdowns for the Sooners (8-2, 5-2).
Knight provided an instant spark after replacing Bell early in the second. Bell was 2-of-5 passing for 10 yards before he appeared to get injured on a fumble with the Sooners trailing 7-0.
Stoops stuck with Bell as his starting quarterback after Oklahoma managed only 237 yards of offense in a 41-12 loss at then-No. 5 Baylor. And while the Sooners got off to another slow start, they outscored the Cyclones 38-0 in the second half.
''We had fun. Like we've said all along, it's not about one guy in this group of quarterbacks,'' Knight said. ''It's the strength of the group. We've got to prepare every week to be ready to go and in situations like that.''
Williams scored on a 69-yard touchdown run in the opening minute of the third quarter, lifting Oklahoma to its first lead of the day. The two-play, 75-yard drive showed the Sooners are capable of scoring in a hurry.
Brennan Clay added a 63-yard touchdown later in the third to extend Oklahoma's lead to 27-10. The two long touchdown runs all but dashed Iowa State's hopes of snapping a 15-game losing streak to Oklahoma.
And Knight made a case for the starting role when he stumbled his way for a 56-yard touchdown on the first play of the quarter. It was the redshirt freshman's first career rushing touchdown.
''He played with poise (and) took care of the football,'' Oklahoma co-offensive coordinator Josh Heupel said. ''He missed a couple of things in the pass, but he handled himself well.''
It was the first time Oklahoma had three players rush for a touchdown of at least 50 yards in a game since 1988.
Stoops said Bell left the game because of an injury and not as a result of his inability to move the offense. Stoops added that the plan was to play Knight as well against Iowa State, but the move came sooner than expected because of Bell's injury.
Stoops said he'll wait until he knows more about Bell's health before he makes a decision on his starting quarterback for Oklahoma's next game at Kansas State.
Oklahoma's offensive woes carried over into Saturday, and things didn't begin to get better until Knight took over.
The Sooners managed just one first down and 25 yards of total offense in the first quarter. It marked the fourth straight game that Oklahoma failed to score in the first.
The Cyclones, losers of seven in a row, jumped out to a 7-0 lead when Sam Richardson ran untouched on a 4-yard touchdown run with 14:18 left in the second quarter.