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It wouldn't make a bit of difference in the final outcome, but Portland State coach Tyler Geving had a point to make during his team's first game against a Top 25 team in nearly three years.

Already down by 18, his Vikings allowed a 13-2 run by No. 20 Oklahoma State to start the second half to put the game out of reach. Geving sent a message by benching all five of his starters, and he was generally happy with the effort he got the rest of the way in an 81-58 loss on Sunday.

"Our effort was a disappointment and an embarrassment to start the second half," Geving said. "So, I went with that second group and they came in and competed for about 7 minutes and did some things offensively and defensively. Then our starters came in and played well down the stretch.

"I just told the guys we have to keep competing and fighting hard. We have to be ready to go to play."

Markel Brown scored a season-high 23 points, Le'Bryan Nash added 20 and the Cowboys (5-0) never trailed in their first game in the rankings in five years.

Phil Forte had 15 points and Marcus Smart collected eight points and nine assists, the third most for a freshman in Cowboys history.

"We're playing with each other, getting each other in good situations to score the ball," Brown said. "Adding Marcus to the point guard spot really helped. He's moving the ball well, putting up crazy numbers in assists.

"We're just playing better as a team overall."

Brown connected on a runner and a 3-pointer and then punctuated the second-half spurt by driving for a two-handed reverse dunk for a 53-24 lead. Portland State (1-3) was never closer than 20 after that.

Renado Parker and Michael Harthun led the Vikings with 12 points apiece. Top scorer Dre Winston Jr., a transfer from Washington State, missed all five of his shots and was held scoreless.

Winston had been averaging 14.7 points and led the team in scoring in each of the first three games this season. Portland State shot 39.6 percent and fell to 0-3 on its four-game road trip.

The Vikings hadn't faced a ranked opponent since December 2009, when they beat rival Portland, which was No. 25 at the time.

"Look at their three guards, they've got three or four inches at every position, so we had a mismatch from the beginning," Geving said. "They'll probably be playing most games in the Big 12 with a size advantage and they have a size advantage on the perimeter playing defense, you can see why they are so good that way."

Oklahoma State went with a seven-man rotation with Brian Williams and Jean-Paul Olukemi both out for the season and Michael Cobbins (toe) and Marek Soucek (knee) still recovering from injuries. Coach Travis Ford held out hope that both might return for next Saturday's game at Virginia Tech.

"We've got to get some guys back. We've played well until this point but we need to get a few guys back," Ford said. "But chemistry has been good. ... Guys have just figured out, because we've had some guys do a lot of different things out there on the court, play a lot of positions, do a lot of different things and they've accepted that and never complained."

The Cowboys climbed into the Top 25 this week for the first time since 2007, following a perfect run through the Puerto Rico Tipoff and an upset of then-No. 6 North Carolina State in the tournament championship game. The game marked the first time Oklahoma State has been ranked in Ford's five years as coach.

He has even higher hopes, though, expressing disappointment that his defense relaxed in the second half as Portland State shot 48 percent, compared to 31 percent in the first half.

"The percentages in the second half for them were not where we want them. We have goals to reach and that's not where we want them," Ford said. "But for the game, they're not bad."

Brown and Philip Jurick came up with blocked shots on two of Portland State's first three possessions and the Cowboys raced to a 14-3 lead, with Smart setting up a right-handed dunk by Brown and a two-handed slam by Kamari Murphy.

The dunks kept coming as Oklahoma State's lead continued to grow, with Kirby Gardner lobbing to Brown for a two-hander coming out of a timeout. Smart then set up three straight baskets — dunks by Brown and Jurick and then a Brown 3-pointer — during a 7-0 stretch that pushed the Cowboys' lead to 31-12 with 6½ minutes left before halftime.

"I felt like we left a lot of points on the floor tonight. I told our team we probably should have scored 100," Ford said. "That's not getting greedy or anything."