LAKE BUENA VISTA, Fla. (AP) - Elias Harris and Kelly Olynyk each scored 13 points to help No. 17 Gonzaga beat Clemson 57-49 in a first round game Thursday night at the Old Spice Classic at the HP Field House.

Olynyk was in the starting lineup after being sidelined since Oct. 26 due to a violation of the student code of conduct that prohibited him for participating in public activities with the team until Nov. 21. The junior forward, who had his first two shots blocked, also had three rebounds. It was his first action since March 19, 2011, after redshirting last season.

Clemson got 10 points from Adonis Filer. Milton Jennings had six points and eight rebounds.

Sam Dower, who was replaced in the starting line-up by Olynyk, had 11 points for Gonzaga (4-0), which will go against Oklahoma in Friday's semifinals at 4:30 p.m. Pacific Time on ESPN2 and the Gonzaga IMG Radio Network including flagship station 1510 KGA in Spokane. Clemson (2-1) will face Texas-El Paso in the loser's bracket.

"It was a very good win for us. We haven't been in a grinder yet and we needed to experience that," Gonzaga head coach Mark Few said. "We need to be successful in an environment like that when a lot of things aren't going well for us."

And things didn't always go well early for the Bulldogs, who, for just the second time this season, shot less than 50 percent form the field for a half. The Zags were 9-for-27 in the first half for 33.3 percent.

But the Zags were a different team in the second half, connecting on 6 of their first 8 shots and finishing 14-for-20 for the half for 70.0 percent. Gonzaga finished at 48.9 percent for the game, the first time in four outings the squad has been under 50 percent from the field.

David Stockton had an end-to-end layup, while Kevin Pangos and Harris added in-close baskets as Gonzaga went ahead 47-39 with 6 1-2 minutes to play. Stockton, who dished out a career-high 7 assists, had five of them in the final 10:41. He found Olynyk for a pair of back-to-back reverse layins to give Gonzaga a41-38 lead with 9:37 to go.

After Stockton went coast-to-coast for a layin, Pangos hit a bank shot from the right side of the lane and Harris had a steal and took it all the way for the layin with 6:37 to go and give the Zags a 47-39 lead.

Harris' 3-point play two minutes later off a Stockton pass made it 50-41, and Stockton found Dower down the lane for another layin and a 10-point lead at 54-44 with 1:53 to play.

"I think we just settled down and let the game come to us late, and that's when those cuts are wide open. Glaringly wide open and they were probably there the first half, too, but we were so frantic we probably didn't see them," Stockton said.

Olynyk scored four points during a 6-0 run that saw Gonzaga go up 31-30 early in the second half. Olynyk had another basket and Guy Landry Edi added a dunk as the Zags grabbed a 37-33 lead with 12 minutes remaining.

But the 7-0 junior from Kamloops, British Columbia, had his first two shots blocked in his return.

"It was a little different. It clicked on me they are actually real athletes, high-level athletes. The coaches tell you, but sometimes the film doesn't do justice. It was kind of an awakening but I just picked things up from there," he said of his rocky start.

Clemson took a 24-23 advantage at the half, which had eight lead changes and three ties.

Gonzaga had the final five points in the first half, including a buzz-beating tip-in by Olynyk.

Damarcus Harrison's 3-pointer gave Clemson a 24-18 lead two minutes before the break. The Tigers scored the first four points of the game and went up 8-5 on a Rod Hall basket.

Pangos' layup put Gonzaga ahead 11-10 with nine minutes left in the first half. The Zags missed 9 of their first 11 shots, and went 9 for 27 (33 percent) during the opening half.

Clemson was 10 of 29 (34.5 percent) from the floor over the first 20 minutes.