PHILADELPHIA (AP) _ Alexander Koul scored 29 points and Kwame Evans had 21 as George Washington defeated St. Joseph's 81-71 Thursday in an Atlantic 10 quarterfinal.

The Colonials (21-6) move on to a semifinal game against No. 2 Massachusetts, the four-time defending tournament champion. George Washington has won its last four games against UMass.

George Washington opened the second half with a 16-4 run and took a 51-39 lead with 14:34 to play on a layup by J.J. Brade. Its biggest lead was 59-46 after a 3-pointer by Evans with 10:36 remaining.

St. Joseph's trimmed the lead to seven on a 5-footer by Reggie Townsend, but Shawnta Rogers followed with one of his 10 assists on a full-court pass to Koul for a layup and a 66-57 lead.

A layup by Will Johnson and two free throws by Terrell Myers cut George Washington's lead to 77-71 with 44 seconds left, but Rogers nailed two free throws to finish it.

Koul's previous high was 28 points Feb. 29 against Rhode Island. He was 11-of-14 from the field and had nine rebounds.

The Hawks (15-12), hoping for an NIT bid, were led by Townsend with 20 points. Rashid Bey added 17.

There were six lead changes in the opening half, which ended in a 35-35 tie. Koul had 16 points in the half, but committed five of the Colonials' 11 turnovers.