Oregon State has been the nation's most improved team, at 10-5 after going 5-27 past year. It was a close game the rest of the half.
Marcquise Reed scored 17 points, Donte Grantham added 16 and Mark Donnal finished with a season-high 13 for Clemson (14-2, 3-1), which had its 10-game winning streak end.
The Wildcats shot 41.5 percent from the field, including 6 of 21 on 3-point attempts. Arizona also gave up eight turnovers, four of them coming in the first eight minutes.
The Beavers shot 39.3 percent overall but 42.9 percent from 3-point range.
OR forward M.J. Cage (4) battles with Arizona State forward De'Quon Lake (35) for a rebound during the first half of an NCAA college basketball game, Thursday, Jan. 11, 2018, in Tempe, Ariz.
Arizona senior point guard Parker Jackson-Cartwright, who's averaging 7.6 points per game and a team-high 4.9 assists, certainly isn't underestimating the Beavers, especially after their 80-77 loss to Colorado in Boulder last Saturday.
Freshman wing Troy Brown, a potential first-round pick, had two fouls in less than three minutes. UA didn't take the lead for good until seven minutes remained, when it went on a 16-3 run.
Sam Hunt fouled DeVoe as he flung up a 3-pointer from the corner.
A 14-2 run by OR in less than 2:30 had the game tied at 41 by the end of the first 20 minutes despite the aforementioned lack of time leading for the Ducks.
However, the official scorer missed two points along the way, and Altman's appeal to the game officials went unheard until halftime when they put the points back on the board, although at first the statistics showed OR ahead 42-41. Dusan Ristic and Parker Jackson-Cartwright trapped Thompson near the sideline and midcourt lines and when Thompson coughed it up, Alkins picked it up and raced in for an expressive reverse dunk that made it 29-26.
However the Ducks refused to go away.
Malachi Flynn led Washington Statewith 24 points, including seven three-pointers. But two scores from Thompson put OSU back ahead 39-38 with 7:48 left.
Over on the Arizona side, they're sitting at 12-4 on the year. Washington State is making 11.8 3-pointers per game this season, two more than any other Pac-12 team.
Allonzo Trier lead Arizona with six points.
The Wildcats cut a 20-point deficit down to as few as three points in the loss to the Buffaloes. Its previous low was 63 in a victory over St. Louis.
Points in the paint were controlled by OR, with 38 points, compared to Arizona State's 16. Drew Eubanks finished with eight points and five rebounds for the Beavers.
The Wildcats fell behind right away, hitting just one of their first six shots while OSU took an early 12-2 lead.
It's a matchup of opposites, with the Wildcats featuring a dizzying offensive attack spearheaded by a three-headed monster of Deandre Ayton, Allonzo Trier and Rawle Alkins-who score 20.4, 19.6 and 15.6 points per game, respectively.
After a slow start offensively, Arizona men's basketball trails Oregon State 22-21 at halftime in the McKale Center.