LOS ANGELES (AP) — Without explanation, South Florida coach Jose Fernandez sent the Bulls into the NCAA Tournament with their top scorer, Courtney Williams, on the bench. The strategy lasted less than 6 minutes.

Williams came off the bench and scored 31 points and No. 6 seed South Florida held on late to defeat Colorado State 48-45 in a first-round game Saturday night.

"That was my decision not to start her," said Fernandez, who declined to elaborate on why he waited until 4:41 into the first quarter, and his team trailing 10-1, to put Williams in the game.

"In my freshman year I came off the bench," said Williams. "I was the sixth man my freshman year so (not starting) took me back to my freshman year. I brought my energy. That's what I did my freshman year. That's what I tried to do tonight"

Williams, a non-starter for the first time this year, scored 18 of the Bulls' 25 second-half points to carry South Florida into the second round where the Rams will meet No. 3 seed UCLA on Monday. The Bruins defeated Hawai'i 66-50 earlier Saturday.

"She is the real deal," said Colorado State Coach Ryun Williams. "The kid is incredible. She's a rock star."

Jamie Patrick scored 17 points and Ellen Nostrum added 12 for Colorado State (31-2), the No. 11 seed and Mountain West Tournament champions. The loss ended a 28-game winning streak for the Rams.

"I love my basketball team," said Colorado State Coach Ryun Williams. "Thirty-three times this team has showed up and put itself in position to win. Not one bad night. Not one time did they not put themselves in a position to win. That's really hard to do."

South Florida forced Colorado State into 13 turnovers, and outscored the Rams 18-4 in points off those miscues.

"I knew going in they were much better than an 11 seed, and they played like it," said Fernandez. "We did enough to survive and move on. We need to close out the game better than we did."

Williams finished 12-of-29 shooting, with the rest of the Bulls combining to make 6-of-31.

"She's really quick," said Ellen Nostrum. "She gets her shot off really high, so it's hard to block it. I just want to contest it every time. We knew she always has a good game so we were trying to stop everybody else from having game."

With South Florida trailing 28-25, Williams scored 12 points in a 15-4 run over 7:46 to push the Bulls to a 40-32 lead at the end of the third quarter.

South Florida led 46-34 when Colorado State reeled off 11 of the next 14 points, pulling within 48-45 on Hannah Tvrdy's 3-pointer with 1:52 to play.

Ellen Gustavsson and Patrick missed 3-point shots to tie in the final minute, and Tvrdy intercepted an inbounds pass with 2 seconds left and called time out as the buzzer went off. Officials ruled no player touched the ball, and awarded Colorado State a final possessions with 1.6 seconds to play.

Sofie Tryggedsson got off a 3-pointer from the left corner as time expired, but the shot rimmed out.

"We had three options on that play," said Williams. "That was the one that was open. She put a good stroke on it. It just didn't go in."

TIP-INS:

Colorado State: The Rams' only other loss this year came at Penn 49-48 on Nov. 24.

South Florida: The Bulls are in the NCAA Tournament for the fourth time in 11 years, carrying a 2-3 Tournament mark with them. Their sixth-seed ties the highest seed the program has ever achieved. South Florida comes into the tournament off its second consecutive appearance in the American Athletic Conference championship game.

UP NEXT:

Colorado State: The Rams' season ends with a 31-2 record.

South Florida: The Bulls play UCLA in the second round of the NCAA Tournament on Monday.