Oklahoma City » Their first second-round game in the NCAA Tournament in 17 years couldn't have started any better for the BYU Cougars.

The first half, though, could not have ended any worse.

Take away the last part of the first half, and BYU played second-seeded Kansas State almost evenly. But that five-minute thrashing by the Big 12 runner-up was more than enough, and the Wildcats rolled past BYU 84-72 in front of 15,688 mostly purple-clad fans at the Ford Center on Saturday night.

Much to the Cougars' chagrin, Kansas State -- and not themselves -- will play in the Sweet 16 on Thursday in Salt Lake City against the winner of today's Pitt-Xavier game.

"Just an opportunity lost," said BYU forward Noah Hartsock. "But there's no shame. We just lost to a terrific basketball team."

There were plenty of reasons why BYU lost, coach Dave Rose said, but most of them can be attributed in some shape or form to the way Kansas State (28-7) played.

"They kind of wore us down," Rose said. "Depth was a big factor in this game."

And so was KSU guard Jacob Pullen, who outdueled BYU's Jimmer Fredette in the key matchup of the game, scoring a career-high 34 points. Running mate Denis Clemente also went deep on the Cougars, scoring 19.

"Those two guards are a handful," Rose said. "They are really good."

Fredette finished with 21, but got some of those in garbage time and was just 5-for-13 from the field while registering the same number of turnovers as assists, five.

The game turned in KSU's favor for good when the Wildcats reeled off a 10-0 run -- seven of those points coming on free throws. The Wildcats scored six straight points without BYU getting the ball past midcourt at one juncture.

"Their [defensive] pressure kind of got to us," Jackson Emery said.

While the Cougars were putting together four straight empty possessions, Pullen was heating up. His 15th point -- on a long three-pointer -- in a span of three minutes, 25 seconds gave the Wildcats a 41-31 lead, and it stood that way going into halftime when officials waved off a tip-in by BYU's James Anderson, saying it came after the buzzer upon review.

"We got in a little lull there where we didn't score for awhile," Rose said. "They caught us, and that gave them a lot of confidence."

After the Cougars raced out to the 10-0 lead, with Emery hitting a pair of early three-pointers, the Wildcats started asserting themselves on the offensive boards, and slowly climbed back into the game.

Kansas State outrebounded BYU 39-29, and, as feared, its 15 offensive rebounds led to 14 second-chance points.

"They're just beasts on those boards," said Hartsock, who had eight points and eight rebounds and was credited by Rose for playing as hard as he has ever played. Hartsock fouled out late in the game.

If there was a key moment in the second half, it came with about 14 minutes remaining when Fredette had a three-point try go in and out that would have trimmed the deficit to three. Twenty-four seconds later, Clemente hit a three for the Wildcats, and a little bit of zeal was drained from the Cougars, who got no closer than five the rest of the way.

"We needed to play a little bit better," Rose said. "But no part of me faults [BYU's] effort. ... [Kansas State's] players just made more plays than we did."

drew@sltrib.com