STARKVILLE (AP) — Mississippi State’s Breanna Richardson had made a grand total of two 3-pointers this season before catching a pass and launching a 20-footer in the most important minute of her team’s most important game.

There was never any hesitation. It looked good the entire way.

It went in.

And it was the defining play in fifth-seeded Mississippi State’s 74-72 victory over No. 4 seed Michigan State on Sunday in the second round of the NCAA Tournament.

“She was ready for the moment,” Mississippi State coach Vic Schaefer said. “And she was ready because of her preparation.”

Victoria Vivians scored 24 points to lead the Bulldogs (28-7), who now prepare for just the school’s second trip to the Sweet 16.

Up next, most likely, is an even bigger dog — No. 1 overall seed and three-time defending national champion Connecticut (33-0) on Saturday.

UConn still needs to get by Duquesne on Monday night, but it’s playing on its home floor where it has won 48 consecutive games. Overall, UConn has won 117 of its last 118 games.

Richardson’s 3-pointer gave Mississippi State a 72-69 lead with 34 seconds remaining. The 6-foot-1 junior was an unlikely candidate to make the game-changing shot — she played just six minutes in the team’s first round win over Chattanooga and was just 2-of-15 (13.3 percent) for the season from beyond the arc until Sunday.

“It was just the fact that I was wide open,” Richardson said. “I shoot 3-pointers all the time in practice, but I don’t do it much in the game. It was just an open opportunity.”

Michigan State had a chance to tie the game with two close shots in the final possession, but both missed. There was a chaotic scramble for the ball in the final seconds and television replays appeared to show Mississippi State’s Kayla Nevitt stepping out of bounds with about four seconds remaining.

But there was no call and the Bulldogs hung on for the win in front of a jubilant announced home crowd of more than 7,000.

“It was a good basketball game — could have gone either way,” Michigan State coach Suzy Merchant said. “It’s unfortunate someone has to lose a game like that.”

Mississippi State led 51-38 early in the third quarter, but Michigan State responded with the next 14 points to take a 52-51 advantage going into the fourth.

Michigan State (25-9) extended its run to 20 straight points by midway through the fourth quarter. The Bulldogs went more than nine minutes without scoring.

Mississippi State fought back and the teams traded the lead down the stretch with several dramatic baskets.

Michigan State was led by Branndais Agee’s 21 points.

Tori Jankoska added 17 points for the Spartans. Jasmine Hines had 15 and Aerial Powers 14.

The game figured to be an intriguing matchup between Michigan State’s balanced offense — which averages more than 75 points per game — and Mississippi State’s defense that gives up around 54.

It was the Bulldogs’ defense that dominated the first half. The Spartans shot 50 percent from the field, but were hurt by 13 turnovers.

Mississippi State got some easy buckets from those turnovers — 14 points in all — which was a big reason the Bulldogs led 40-34 at halftime. Morgan William and Vivians both had nine first-half points.

William finished with 14 points, including two free throws in the final seconds.

Mississippi State looked like it might pull away for good when it stretched its lead to 51-38, but Michigan State finally found some room to work on offense and went on a 20-0 run.

Michigan State led 58-51 with 7:44 left, but then it was the Bulldogs’ turn to respond.

Vivians hit a much-needed 3-pointer to give the Bulldogs momentum and then Richardson made a layup to push Mississippi State ahead 61-60. Richardson hit an even bigger shot minutes later to send the Bulldogs to the Sweet 16.