LOS ANGELES - Months ago, after their early-season magic started disappearing, the Arizona Wildcats developed a painful habit of losing their defense at times.

Often, it was for an entire half, or an extended stretch, and it would cost them the game (Cal, at USC) or give them at least a scare (Colorado at McKale, at Utah).

On Thursday, in Arizona's 73-70 loss to Ohio State in the NCAA West Region semifinal, it was a little different. The defensive lapse was for just a few minutes after halftime, fueled in part by UA offensive struggles that turned into easy OSU baskets, and there was another lapse in the final seconds at Staples Center.

But considering it came against the second-seeded team in the West, the champion of the Big Ten tournament, and against a battle-tested program that visited last season's Final Four, that's all it took.

The Buckeyes did not need an entire half or a long stretch of UA troubles to take advantage. Ohio State wiped out UA's early leads of up to 11 points by going on a 22-5 run combined between the end of the first half and the beginning of the second half.

"The first two minutes (after halftime) they played harder than us," forward Kevin Parrom said. "We fought back, but it wasn't enough."

It wasn't enough because it left OSU with 22 seconds to run off a final play with the score tied at 70.

OSU point guard Aaron Craft started initiating the offense when the clock ticked into single digits, and suddenly found LaQuinton Ross open on the left side of the wing when UA failed to switch properly off the ball screen.

Craft, who nailed a game-winner in the Buckeyes' previous win against Iowa State, said he thought he might have to try another. But he never had to.

"They'd been switching that ball screen, but for some reason they didn't switch, they didn't communicate very well," Craft said. "I had the easy job. I saw Q was open, got him the ball, and he knocked it down for us."

UA coach Sean Miller, while repeatedly praising his team for playing hard, couldn't help but note that the Wildcats had switched on "probably 400 handoffs and ball screens" but did not on the last one.

So that was it. UA had two seconds to tie the game, but never got off a shot, and the college careers of Los Angeles native Solomon Hill and Lyons, who led all scorers with 23 points, were over. And so, too, quite possibly was the career of Parrom, who appears unlikely to receive a medical hardship waiver for a fifth season.

Even though Hill had nine of his 16 points over a four-minute span in the second half, and Lyons had both an opening flurry of success and the late game-tying drive, there wasn't enough this time for some last-second help.

Lyons' drive tied it but left too much time for Ohio State to go ahead, and Hill's nine points midway through the second half cut the Buckeyes' lead from 10 points to four.

Thanks to their early second-half success, the Buckeyes had enough to hang on. UA led 33-22 with 6:24 left in the first half after a pair of free throws from Parrom, but OSU cut UA's lead to 38-34 by the end of the half.

Then, OSU went on a 10-0 run to start the second half, taking advantage of a number of transition opportunities while the Wildcats' offense sputtered. UA missed its first five shots of the second half and turned the ball over twice.

"I think the biggest change in our offense was our defense," Craft said. "We got some steals. We were pushing it and I think our offense is best when we run in transition. We got some easy buckets."

They also made some difficult ones, as their smaller lineup found success against the bigger Wildcats.

"The game changed dramatically for us on defense," Miller said. "We had a hard time guarding dribble drives. We went small; and as we went smaller, they got some pivotal second shots."

Ohio State wound up out-rebounding UA 17-13 in the second half of a game when statistics were remarkably close across the board. Both teams took 52 shots; UA made one more of them (23) but had three more turnovers (11) than did the Buckeyes.

"We just had trouble defending them one-on-one," center Kaleb Tarczewski said.

It was that close. In the big picture, UA's defense didn't really desert them all that much - OSU shot 45.5 percent in the second half and 42.3 percent for the game - but it did just enough.

Arizona's season ended at 27-8, just a few points shy of reaching their second Elite Eight in three seasons. The Buckeyes moved on at 29-7.

"It would have been interesting to see if it went into overtime," Miller said. "Losing in this tournament, when you play all the way to the end, hurts more. But I think you leave with a lot of pride knowing that you played your heart out, and we really did that."

On StarNet: Find more photos from the game at azstarnet.com/gallery

Download the Star's updated NCAA tournament bracket at azstarnet.com/pdf