LAHAINA, Hawaii -- Dayton loves Hawaii -- and not for the surfing. The Flyers much prefer fishing for wins against ranked teams.
Dyshawn Pierre hit four free throws with less than 30 seconds left and Kyle Dranginis narrowly missed an open 3-pointer that could have tied it for the Bulldogs in the final seconds. Gonzaga (4-1) led by as many as 16 in the first half.
"The second half, the guys were ready to play," Dayton coach Archie Miller said. "From that point forward, we were the team we wanted to be."
Sibert had 16 points in the second half as the Flyers (5-0) came back to give this year's tournament its first major upset.
Dayton took its first lead during a 7-0 run with less than 12 minutes to play after cutting into Gonzaga's lead as soon as the second half began. From there, it was a back-and-forth game.
"Our guys weren't panicked at halftime at all," Miller said. "At halftime we talked about a few things and our guys were able to do those. The way we rebounded the ball and made shots, that's what college basketball is about."
Dayton shot nearly 61 percent in the second half after hitting less than one-third of its shots in the first 20 minutes. The Flyers responded each time Gonzaga attempted to regain control, hitting big shots and free throws to stave off any sustained comeback.
Kevin Pangos paced the Bulldogs with 27 points and nearly led a comeback to save his team from the loss, coming up with steals, layups and drawing fouls to keep Gonzaga within striking distance. But he fouled out in the final minute and could not contribute to the last two possessions.
"I just kind of blanked [out] there. Some of the coaches were telling me. That was my fault," Pangos said. "I should have known the foul situation. If I knew I wouldn't have gone for it, but I just blanked."
Pierre had 15 points and nine rebounds. Devin Oliver scored 12 and Khari Price 11 for the Flyers.
Sam Dower Jr. -- who sat on the bench with foul trouble during some critical possessions late in the game -- scored 18 points and shot 8 for 10 from the floor for the Bulldogs. Gary Bell Jr. had 12 points.
"We were battling foul trouble all game long so we had some strange lineups and scenarios out there, but Dayton did a great job staying with the game and they handed it to us," Gonzaga coach Mark Few said.
Dayton also beat No. 12 UConn and No. 6 Maryland during the 2000 tournament in Maui. The Flyers will play No. 18 Baylor on Tuesday with a spot in the finals at stake.
Gonzaga will play Division II Chaminade in the losers' bracket.