SAN JOSE, Calif. (AP) -- Dominic Artis anticipated Marcus Smart's pass and took the interception the other way for a layup early to set the tone for Oregon.
Despite the seedings and the all the pregame hype surrounding Oklahoma State's star, the Ducks had the better team and the better freshman point guard Thursday night.
Artis had 13 points, four steals and helped slow down Smart while fellow freshman Damyean Dotson led the way with 17 points to help 12th-seeded Oregon extend a run that began in the Pac-12 tournament by beating the fifth-seeded Cowboys 68-55 in the second round of the NCAAs on Thursday.
''We wanted to be aggressive on the boards, we wanted to be aggressive defensively and we wanted to be aggressive offensively,'' coach Dana Altman said. ''I thought our guys did a great job of that. DA got it started off with a steal and layup early. I'm really happy for these two freshman guards. They're the future of our program and to get experience like that, it was really important.''
Arsalan Kazemi added 11 points and 17 rebounds to give the Ducks (27-8) their first tournament win in six years.
Oregon advanced to play fourth-seeded St Louis (27-6) on Saturday for a spot in the Midwest regional in Indianapolis next week. The Billikens beat New Mexico State 64-44.
The selection committee raised some eyebrows when Oregon was given a 12 seed despite tying for second place in the Pac-12 in the regular season, winning the conference tournament and going 21-4 with Artis in the lineup.
''I never felt like we needed to make a statement,'' forward E.J. Singler said. ''We knew we had a good team. It was about getting the win and feeling good about ourselves.''
Oklahoma State coach Travis Ford said before the game that the Ducks looked nothing like a 12 seed and that was proven true in their tournament opener with the way they shut down Smart and hit their outside shots. Oregon's eight 3-pointers were their most since having nine in December against Houston Baptist.
''We ran into a very hot team, a very hot team,'' Ford said. ''I've watched a lot of games on these guys and how they've played the last three games compared to how they were playing two or three weeks ago, this was a hot basketball team. I was impressed with Oregon, really impressed and they came in here playing extremely well.''
Smart came into the game with the hype of a top NBA prospect but was held to 14 points on 5 for 13 shooting a disappointing finish to a stellar season for the Cowboys (24-9).
''I definitely wish I could have done more for my team,'' Smart said. ''I feel like I let my team down. I didn't contribute to my team the way that I usually do. And it hurt us a little bit.''
Smart hurt his right hand in the second half and was scheduled to have tests to determine the extent of the injury. His future is also in question and Ford said he would talk with his star player soon about whether to enter the NBA draft.
It was the Ducks' freshmen backcourt that shined on this night with Dotson hitting three 3-pointers in the first half to help build the lead and Artis shining on both ends.
Artis frustrated Smart and also hit a 3-pointer that gave the Ducks a 54-38 lead midway through the second half in his best performance since missing nine games with a foot injury during the conference season.
''I made some shots that I usually hit, so that got me going,'' Artis said. ''And then focusing on defense really helped the team.''
His return late in the year helped pave the way to the Pac-12 tournament title for Oregon and has the Ducks playing their best at the most important time of year.
Smart picked a bad time for one of his worst performances. He turned the ball over five times, missed four of eight free throws and was unable to exploit his decided size advantage against Artis and Johnathan Loyd on the offensive end.
He didn't get much help either outside of 16 points from Markel Brown.
''It's frustrating,'' said Le'Bryan Nash, who was held to 10 points. ''Winning 24 games, that's still a remarkable season but being a fifth seed, it hurts a lot. I want to cry right now but I can't. I'm really hurt right now.''
The Ducks had a decided crowd advantage for the game played on the West Coast with even former UCLA star Bill Walton decked out in a tie-dyed Oregon outfit.
There was plenty to cheer about in the first half for the Oregon fans after a sloppy start to the game that featured 10 turnovers in the opening 9 minutes.
Artis picked Smart twice to lead to fastbreak baskets for the Ducks. Kazemi's slam on a putback gave Oregon a 19-12 lead as the Cowboys went nearly 6 minutes without scoring.
Carlos Emory's 3-pointer from the corner made it a double-digit game with just over a minute left and Kazemi beat the buzzer with a reverse off an airball by Dotson to give Oregon a 37-26 lead at the half.