"You thought we were down and out. No way," said Bradlee Van Pelt, who passed for 192 yards and three touchdowns for the Rams.
The previous record for an opponent had been 49 points. The Rams had that nearly in the first half when they took a 41-13 lead. Even with the starters getting a breather through much of the second half, Colorado State (4-3, 1-1 Mountain West) continued to keep BYU (3-4, 2-2) out of synch while adding to the rout.
"We expected to come out and play a good game. We know what kind of team we are," said Van Pelt, who completed 8 of 11 passes with no interceptions and ran 12 times for 51 yards before heading to the bench after just one series in the third quarter. "We've got to find ways to keep it up."
Marcus Houston had 18 carries for 85 yards and three touchdowns as the Rams avoided an 0-2 start in the Mountain West. The defending conference champions gained 446 yards of offense while scoring their most points since a 55-20 win over San Jose State in 1997.
The Cougars, who snapped a two-game losing streak last week with a 44-36 win over San Diego State, never recovered from some early blunders and lost to Colorado State in consecutive seasons for the first time since 1964 and '65.
"I'd say we're starting to gain momentum," Van Pelt said. "We're starting to play Ram football. It's something we've played in the past years, but for some reasons in the first five games we couldn't hit our stride."
BYU was booed loudly and often by the homecoming crowd of 58,377 and received mock cheers for even minor accomplishments like first downs. No one had clobbered the Cougars at home like this since Arizona State beat BYU 49-17 in 1972.
"Well, they just took it to us," BYU coach Gary Crowton said. "They're a good football team. They were ready to play and played well in all areas."
The Rams broke the record with a few late scores in the second half, but the real damage was done in the first half as Colorado State took advantage of turnovers and shoddy defense to score six touchdowns.
John Beck was 10 of 23 for 136 yards with an interception and a touchdown and Matt Payne kicked two field goals for BYU, which was shut out in the second half. About the only breaks the Cougars caught were a Colorado State interception that was fumbled into the end zone for a touchback and a fumbled punt return that led to BYU's only touchdown.
The Cougars will try to regroup next Saturday at Wyoming.
"It's disappointing," Crowton said. "But that's the great thing about football. There's a game next week."
Almost all of Thursday's highlights belonged to the Rams, who led 41-13 at halftime. Van Pelt was 5-of-8 for 147 yards and three touchdowns, and carried nine times for 47 yards in the first half as Colorado State gained 263 yards and scored its most points in the first half since going up 42-17 against Texas-El Paso in 1973.
Two of the touchdowns were to Eric Hill, including a 25-yard play that Van Pelt turned from a near sack into another score that put the Rams ahead 34-13 late in the second quarter. Van Pelt's other TD pass was to Matt Bartz, who was all alone on the left sideline and rumbled in untouched for a 59-yard touchdown.
"Essentially it's a misdirection," Van Pelt said. "I think coming on that play BYU was overplaying and sure enough, they tried to overcompensate and we hit it perfectly."
The Cougars hurt themselves with three turnovers, two of which led to touchdowns and a third that nearly did. Beck fumbled as he was sacked and defensive end Patrick Goodpaster scooped it up and ran 16 yards for a touchdown that gave the Rams a 27-10 lead early in the second quarter.
Then later in the quarter, the Cougars coughed it up again when Marcus Whalen dropped a handoff and the Rams recovered at the BYU 19. The end result was a 1-yard touchdown run by Houston that gave the Rams the huge halftime lead.
BYU's biggest break in the half was a fumbled punt return that the Cougars recovered at the 9 and turned into a touchdown on a pass from Beck to Justin Jory to make it 21-10. Payne added his second field goal of the half, but that was the last of the scoring for the Cougars.