TYSONS, Va. – Riley Iffrig cranked a ninth-inning grand slam to lift the No. 3 Billikens past second-seeded George Mason, 5-3 Wednesday in the Atlantic 10 Baseball Championship second round at Capital One Park.

The Billikens (33-24) advance to the semifinals to face top-seeded Rhode Island at 3:00 pm on Friday. George Mason (37-20) falls into the consolation bracket and will play No. 5 Saint Joseph’s at 3:00 pm Thursday.

Iffrig’s bases-clearing homer erased a 3-1 Patriots lead that they built with single runs in the first, second and sixth innings. George Mason added drama in the bottom of the ninth, loading the bases with a walk off win threatened, but James Quinn-Irons hit a comebacker up the middle that found its way between the pitcher’s legs and directly into Ethan Sitzman’s glove to end the rally chance.

Quinn-Irons hit a first-inning solo home run for the first score of the game. A Jonny Wall bunt single sent Andrew Rayo home in the second, and Raymo had a sacrifice fly in the sixth to score Quinn-Irons.

Prior to Iffrig’s heroics, the only SLU run came from Brandon Stressler’s bat on a sac fly that plated Hayden Moore.

Reliever Charlie Weber (4-1) got the win for the Billikens with 3.2 innings of work and no runs, two hits, three walks and two strikeouts. Gardner Meeks (L, 3-2) went one inning, allowed two hits and two runs with two strikeouts.