She was 0 of 8 from the field before her layup with 41 seconds left in overtime lifted the No. 5 seeded Lady Cowgirls past 12th-seeded Florida Gulf Coast, 61-60.
''I wanted to try to make people attack me so I could at least get to the free-throw line,'' said Bias, who added eight assists. ''I had a lot of determination there. I had the mindset that I had to provide strength at that time. It's one of those things where you know you have to make it.''
The Cowgirls (24-8) will play No. 4 Purdue or No. 13 Akron in the second round of the Notre Dame regional on Monday night.
The teams traded the lead in OT before Bias' layup. Florida Gulf Coast (26-8) missed a shot with that would have given the Eagles the lead. Oklahoma State was fouled with 3 seconds left, but Liz Donohoe missed the free throw. Florida Gulf Coast had a chance, but Brittney Martin stole the inbounds pass with a second left.
She was fouled and missed her free throw. That gave the Eagles one final chance, but they couldn't get a shot off.
''Had we made our free throws at the end, it would have helped us a lot,'' said Martin, who finished with nine points and 15 rebounds. ''We knew we had to pull it out at the end. We knew they were eying to get the ball to (Whitney Knight), who had the hot hand. We needed a steal.''
Oklahoma State was fortunate to force OT. The Cowgirls trailed by six late in regulation, before going on an 8-0 run capped by Bias' free throw with 54 seconds left that gave the Cowgirls a 57-55 lead. Kaneisha Atwater's layup tied it with 35 seconds left. Neither team could score in the rest of regulation.
Roshunda Johnson led Oklahoma State with 11 points.
''I've already got about 50 texts telling me that it is about survive and advance,'' Oklahoma State coach Jim Littell said. ''That's a very good Florida Gulf Coast team. We knew going in that it was a very tough guard for us in the fact that they spread you out, drive and then shoot so many 3s.
''In the 36 or 37 years of coaching, you look back after one like this and say, ''How did we win that game?''
Jenna Cobb had 16 to lead the Eagles, who had their 12-game winning streak end. They had won 21 of their previous 22 games. FGC made 7 of 29 attempts from 3-point range and only 1 of 6 in overtime.
The Eagles got 3-pointers from Knight, Cobb and Knight again to take a 47-40 lead with 12:17 remaining. A free throw from reserve guard Stephanie Haas and a basket from Atwater increased that advantage to 50-40 with 10:22 to play.
Florida Gulf Coast missed 16 of its first 19 field goal attempts and fell behind 20-9 with 7:24 remaining in the first half before receiving a spark off the bench from Haas, whose 12 opening-half points helped the Eagles finish with a 19-8 run and 28-28 tie at intermission.