Buddy Hield scores 27 points for No. 1 Oklahoma, but three players score 20-plus points for No. 19 Iowa State in an 82-77 victory over the Sooners. (1:37)

No. 1 goes down again: Oklahoma falls to Iowa State (1:37)

AMES, Iowa -- Another No. 1 team came to the state of Iowa.

Another No. 1 team left with a loss.

Georges Niang scored 22 points and Monte Morris added 20 as No. 19 Iowa State beat top-ranked Oklahoma 82-77 on Monday for its first win over a No. 1 team since toppling Wilt Chamberlain's Kansas Jayhawks in 1957.

Morris had a jumper, a key rebound and two free throws in the final 21 seconds for the Cyclones (14-4, 3-3 Big 12), who were actually slight favorites at home.

It was the third time this season that a No. 1 team lost within Iowa's borders. Northern Iowa beat North Carolina, and Iowa beat Michigan State.

"Basketball is alive and well here," said Niang, who grew up in Massachusetts. "Basketball is at an elite level in Iowa."

Oklahoma, which moved to No. 1 earlier Monday for the first time in 26 years, didn't go down quietly. Isaiah Cousins hit a 3 with 41 seconds left to tie the game at 75. But Morris drilled a step-back jumper for the lead, and Abdel Nader's free throws with 3.1 seconds to play put the game out of reach.

Buddy Hield scored 27 points, and Cousins had a career-high 26 for the Sooners (15-2, 4-2). Oklahoma could make a case for retaining the top spot with a win Saturday at No. 13 Baylor.

Oklahoma's two losses came in two of the toughest places in the country to play. The Sooners fell in triple overtime at Kansas in arguably the best game of the season so far.

"We came ready to play," Hield said. "But Iowa State had more fight than us."

Iowa State nearly beat Oklahoma on the road in the Big 12 opener earlier this month. The Cyclones led for 30 minutes, but Morris missed a wide-open 3 with six seconds left, and the Sooners escaped 87-83.

This one was just as entertaining. But this time, Morris finished off the Sooners.

Matt Thomas drilled a 3 early in the second half to give Iowa State its first double-digit lead 48-38. But the Cyclones came up empty on a few possessions that just might have put the game out of reach, and the Sooners rallied to jump back ahead 59-57 on a long, shot clock-beating 3 from Dante Buford.

Iowa State responded with 10 straight points, a run highlighted by Niang's casually drilling a 3 to beat the shot clock for a 67-59 lead. The Sooners made it all up in 79 seconds though, which set up another thrilling finish.

Nader scored 20 points for the Cyclones, who won despite allowing Oklahoma to hit 10 of 16 3s in the second half.

Iowa State has now won two straight after a 1-3 Big 12 start that threatened to derail its league title hopes.

"They all stuck together, and it just shows our character," Iowa State coach Steve Prohm said. "It's about the players, and [Niang and Morris] were tremendous."

TIP-INS

Oklahoma: The Sooners entered play ranked first nationally at 45 percent on 3s. Iowa State's fans noticed and at times went silent when Oklahoma shot 3s, as if they were expecting them to go in. ... Perhaps Hield's most impressive 3 was a fadeaway that tied the game at 67 with 3:55 left.

Iowa State: The Cyclones outscored Oklahoma 30-8 in the paint in the first half, but the Sooners buried seven 3s to keep it within 41-35. ... Reserve guard Hallice Cooke, who was suspended for Saturday's 76-63 win at Kansas State for violating team rules, didn't play Monday.

STAT LINES

Iowa State, which has at times struggled with rebounding, grabbed 11 more than Oklahoma. ... Cousins went 10-of-15 from the field. ... The Cyclones won without a point from their bench. ... Jordan Woodard was the only Sooner cold from 3-point range, as he went 1-of-5 and scored eight points.

QUOTABLE

"We didn't rebound the ball like we need to, especially on the road," Oklahoma coach Lon Kruger said.

UP NEXT

Oklahoma travels to No. 13 Baylor on Saturday.

Iowa State plays at TCU on Saturday.