NORMAN, Okla. (AP) -- Oklahoma won a game it couldn't afford to lose. Iowa State may have won over any skeptics.

Eduardo Najera scored seven of his 25 points in the second overtime, and Tim Heskett added two big 3-pointers as the Sooners (No. 16 ESPN/USA Today, No. 17 AP) beat Iowa State 80-75 on Saturday.

The Cyclones came in with a school-record 13-game winning streak and proved it was no fluke, erasing a 14-point deficit in the final 6½ minutes of regulation and then forcing the issue for 10 more minutes.

"We desperately did need to win this basketball game," Oklahoma coach Kelvin Sampson said. "Our kids bent and Iowa State kept putting it to us, but you find out a little bit about a team through adversity."

Najera also had 14 rebounds. Heskett scored 18, all on 3-pointers, helping the Sooners (15-3, 3-2 Big 12) end a two-game losing streak. Both those losses came on the road.

"You're going to lose some games on the road, but you've got to defend your home and that's what we felt we had to do," Heskett said.

Iowa State (16-3, 4-1 Big 12) scored a season-low 19 first-half points before coming back. The Cyclones had opportunities to win at the end of regulation and the first overtime, then dug too deep a hole in the second extra period.

"We had our chances and didn't capitalize on them," coach Larry Eustachy said. "I thought our team really made some great plays down the stretch to even make it a game."

Big 12 scoring leader Marcus Fizer finished with 20 but didn't score after regulation. Michael Nurse had 19 and helped carry the Cyclones back after it appeared Oklahoma would coast to the victory.

The Sooners went 13-of-27 from 3-point range. They made six of those in the first half, when they twice led by as many as 16. After halftime, consecutive 3-pointers by J.R. Raymond and Heskett gave Oklahoma a 52-38 lead with 6:47 to play.

But Nurse scored eight points as the Cyclones rallied, scoring on nine of their 12 possessions. Meanwhile Oklahoma, which had only two turnovers in the first half, committed 12 in the second half.

Nurse's 3-pointer with 1:38 left made it 59-all and proved to be the final basket of regulation. Oklahoma Iowa State turned the ball over with 42.9 seconds left, OU's Raymond missed a shot with 8 seconds and Jamaal Tinsley's runner in the lane rolled off the rim.

"I want to see that layup. I just cannot believe that ball didn't go in by Tinsley," Eustachy said.

Oklahoma got two baskets from Victor Avila in the first overtime, the second coming with 32 seconds left to give the Sooners a 63-62 lead. Nurse got fouled on a drive to the basket with 4.8 remaining. He tied the score with his first free throw, but missed the second and Heskett's potential game-winning 3-pointer at the buzzer missed.

Heskett's first 3 of the second overtime gave Oklahoma a 66-65 lead. After Tinsley scored on a short jumper to give the Cyclones the lead, Raymond got a kind bounce on a 3-pointer and Najera converted a three-point play -- his first basket of either OT -- to make it 72-67.

Heskett's final 3-pointer, on a pass from Najera, gave the Sooners a 75-69 lead. Najera added four straight free throws as Oklahoma widened the lead to nine in the final 30 seconds.

Raymond scored 20, including six 3-pointers. Tinsley finished with 17.

The loss, the Cyclones' first since Nov. 28, prevented them from tying the best start in school history.