Morningside Loses at Finish : Division III: Kameisha Prewitt’s last-second shot to tie the game misses and Costa Mesa wins, 49-46.

The Morningside girls’ Southern California Division III regional title hopes came down to the last shot Saturday at the Sports Arena, but the Monarchs’ Kameisha Prewitt had her three-point attempt bounce hard off the backboard as time expired to give Costa Mesa a 49-46 victory.

Senior forward Olivia DeCamilli had a game-high 24 points and 11 rebounds for the Mustangs (28-4), who play Northern California champion Sacramento St. Francis on Saturday at Oakland.

Morningside finished 28-3.

The 5-foot-10 DeCamilli also stood out defensively, holding Morningside senior center Tina Thompson to a team-high 19 points on eight-for-23 shooting.

“I just tried to stay in her face,” said DeCamilli, who has signed a letter of intent to attend San Diego State in the fall. “I knew she got her points off rebounds and I tried to box her out really hard.”

The 6-foot-2 Thompson had 19 rebounds. Her rebound and basket with 40 seconds left cut the Monarch deficit to 49-46.

The Mustangs held the ball and DeCamilli missed a shot with 11 seconds remaining. Thompson grabbed the rebound and passed to point guard Prewitt (12 points), who raced to the right side and launched the three-point shot that hit nothing but glass.

“I thought it was overtime,” said Costa Mesa senior forward Neiar Kabua, who scored 11 points. “It really scared me.”

But the shot appeared to anger Thompson, who stormed into the locker room and missed the awards ceremony.

Morningside shot 29% from the field and the Mustangs made 30% of their shots. The game was decided on the foul line, where the Monarchs made only five of nine shots. The Mustangs were 13 for 21.

Costa Mesa’s man-to-man defense caused problems for the taller Monarchs.

“We wanted to get (the ball) inside,” Monarch Coach Rod Tatum said. “But they collapsed more than anyone else has done and it worked real well.”

Costa Mesa Coach Lisa McNamee knew the Monarchs’ strengths.

“When (the players) came over to the bench (during the game), I asked them, ‘What is Morningside going to do? They’re going to go inside,’ ” McNamee said. “Then what? ‘They’ll go to (Prewitt) for a three-pointer.’ ”

The Monarchs made only three of 18 three-point attempts and Prewitt was only two for nine from the distance.

Costa Mesa passed through the Monarchs full-court defense and led, 23-20, at halftime. But a Monarch spurt that started late in the third quarter and continued into the fourth tied the score at 40 with 6:30 remaining.

A 7-0 run by Costa Mesa gave it a 47-40 lead with 2:26 left, but two baskets by Thompson and one by Cha-Ron Walker brought the Monarchs to within 49-46.

Walker had eight points and seven rebounds. Costa Mesa forward Jessica Lurmann had 14 rebounds and 5-7 point guard Yool Kim had 11.