Once is a mistake, twice is a pattern, but Oklahoma head coach Porter Moser is gonna do everything in his power to make sure there won’t be a third time.

For the second occurrence this season, the Sooners blew a comfortable lead late in the second half to taste defeat. This time around it was a 66-62 overtime setback against visiting Butler on Tuesday evening.

The loss puts OU at 7-2 overall and ends its 26-game home winning streak against non-conference opponents.

Take your pick, OU was up 44-32 with 11:53 left in the second half. The Sooners were up 49-41 with 8:22 left and then failed to score for the next eight minutes.

A 3-2 zone employed by Butler put the clamps on OU’s offense. The Sooners couldn’t find the soft spot in the zone, passing it around the perimeter and taking low-percentage three-pointers. Empty possession after empty possession.

Add it all up, and OU went 9-31 (29 percent) from beyond the arc and shot just five free throws in the entire game.

“No, no I was not happy. We work so much on getting the ball in the middle of the zone,” Moser said. “And the crazy thing about it is they’ve played eight possessions of zone all year, but we literally worked on it for three or four days. Every day, we did a zone segment in practice. So we just said to ourselves even though they’ve only played eight possessions all year, we felt if we were really getting our man going, they were going to go to that zone.

“It starts with me. I’ve got to get our guards to know how to play it. We’ve got to bring them up, get it, hit a gap. I just thought we were playing catch against the 3-2 zone and then settled for a 3. I’m going to get Jordan better, I’m going to get EJ better, I’m going to get Mo better and Jalen better. It starts with me.”

All that being said, Elijah Harkless still almost got to play hero. With OU down 54-51 with 10 seconds left, Harkless drained a 3-pointer between the wing and the corner to tie the game with 2 seconds left.

He continued in overtime with another from downtown as did Jordan Goldwire to give OU a 62-58 lead with 1:38 left in the extra period before Butler ended the game on an 8-0 run to secure the upset.

OU was outrebounded 43-30, and the Sooners only had three second-chance points for the game.

“You can't get outrebounded by 13,” Moser said. “You just can't. We're not that team. We have to be really good at a lot of things – boxing out is one of them. They had some athletic long guys that were just going to get the rebound. We're going to see that a lot. We're going to see that a lot coming up.”

Harkless led the way with 16 points, while Goldwire and Tanner Groves each pitched in with 10 points. Groves didn’t score after the first half, though.

It does not get any easier for Moser’s club as OU plays No. 12 Arkansas (9-0) on Saturday afternoon at the BOK Center in Tulsa.