OLEAN, N.Y. (AP) _ James Singleton scored a season-high 22 points and St. Bonaventure held off a late rally for an 80-77 upset of No. 13 Xavier on Saturday in the Atlantic 10 opener for both teams.

The Bonnies (10-3) trailed only once in the game before completing one of its biggest upsets in years and winning its first conference opener since 1989.

Xavier (8-3) came in with its suffocating defense, but St. Bonaventure broke it down with quick guard Tim Winn. Caswell Cyrus was the biggest beneficiary with three layups and a dunk in the second half.

Singleton, who came into the contest averaging 6.7 points per game, scored 14 points in the first half. Winn added 16 points and Cyrus and Rashaan Palmer each had 14.

It marked the first time in nearly four years that St. Bonaventure beat a ranked team. The Bonnies beat No. 19 West Virginia 72-66 on Jan. 29, 1994 at the Reilly Center.

Gary Lumpkin led Xavier with 18 points, while Tyrone Braggs added 14.

St. Bonaventure built a 52-39 lead on Cyrus' layup with 14:44 remaining, and the Bonnies hung with Xavier picking up its full-court defense in the final eight minutes.

The Bonnies had a 78-68 lead before Brown hit two 3-pointers and cut the margin to 79-75 with 18 seconds remaining. It was too late for the Musketeers. St. Bonaventure made 10 of 13 free throws over the final four minutes after shooting just 59 percent from the line coming into the game.

Lumpkin brought the Musketeers within 70-63 with an 18-foot jumper with 2:20 remaining before Singleton pushed the Bonnies' lead to 74-63 with 1:53 remaining.

Xavier, which was ranked as high as seventh earlier in the season, was a victim of its own poor shooting. The Musketeers shot 40 percent from the field, including 5-of-22 from 3-point range.