After he threw an interception and had a fumble returned for a touchdown in the first quarter in heavy rain as Houston fell behind 17-7, he changed his opinion.
"I hate rain games," Keenum said he was thinking. "This is terrible."
Keenum got going after the rain subsided and threw a career-high nine touchdown passes to break the Football Bowl Subdivision record for career TD tosses in the No. 18 Cougars' 73-34 victory.
With the rain at its heaviest, Houston coach Kevin Sumlin expressed his disbelief at the weather.
"I said, 'Surely it's not going to be like this all night. It can't rain like this all night,"' he said. "I guess somebody heard me because it started to stop after that."
After falling behind 17-7, Houston outscored Rice 45-3 to take a 52-20 lead early in the third quarter and cruised to the easy victory to remain undefeated.
Keenum, who became the FBS career leader in total offense last week, has 139 career touchdown passes.
He abused Rice's 115th-ranked defense by throwing TD passes of 57, 21, 64, 18, 41, 20, 37, 22 and 47 yards to break former Texas Tech quarterback Graham Harrell's record of 134.
"It was a blast," Keenum said. "That was probably the most fun I've ever had playing football."
He had so many touchdown passes, he couldn't remember all of them when asked to recount them.
"Maybe if I thought about it, (but) I don't know if I could list them off to you right now," he said.
Patrick Edwards had seven receptions for 318 yards receiving and five touchdowns for Houston (8-0, 4-0 Conference USA).
Tyler Smith had 170 yards rushing and two rushing and one receiving touchdown for Rice (2-6, 1-4). That included a 97-yard scoring run -- the longest TD run in school history.
The Owls led 17-7 late in the first quarter before Keenum threw his first touchdown pass for 57 yards to Edwards. The teams exchanged field goals at the beginning of the second quarter to leave Rice up 20-17.
Keenum then threw three touchdown passes in a 6-minute span at the end of the first half to put Houston on top 38-20 and tie the touchdown passes record.
He broke the record on a 41-yard pass to Charles Sims early in the third quarter to push the lead to 45-20. Keenum smiled and flashed the Cougars hand signal when he appeared on the jumbotron on the sideline.
He was 24 of 37 for 534 yards before giving way to backup Cotton Turner with 8 minutes remaining.
"Those are video-game numbers, something we couldn't get stopped," Rice linebacker Justin Allen said. "The rain slowed down a little bit ... I wished it would have rained all game. It stopped, and they got things cranked up. There was no looking back for them."
Keenum, granted a sixth year of eligibility after tearing a knee ligament early last season, needs 267 yards passing to become the FBS's career leader in passing yards. Former Hawaii star Tim Chang holds the mark of 17,072.
Tyron Carrier tied the NCAA record for career kickoff returns for touchdowns with seven by returning the opening kickoff 100 yards for a score. Carrier dashed down the right sideline and darted around the defense virtually untouched before outrunning the kicker for the score.
Actually, Carrier said no one got a finger on him on the return.
"Not a touch," he said. "That's the way it should be."
He shares the record with former Clemson returner C.J. Spiller.
Carrier also had a touchdown reception, Sims had two and Justin Johnson added one for the Cougars.