When South Portland guard Matt Pelletier missed badly on a shot early in the game, he knew things could only get better.

“I airballed it my first shot of the first half,” Pelletier said. “Coach told me I have the green light, so in the second half I just kept shooting.”

And he started hitting his shots.

Pelletier scored all 22 of his points in the second half to help No. 2 South Portland pull away and beat No. 7 Cheverus 65-45 in a Western Class A boys’ basketball quarterfinal Monday at the Portland Expo.

The Red Riots (16-3) advanced to play No. 3 Falmouth in the semifinals Friday night at Cross Insurance Arena. Cheverus, which reached the quarterfinal with a 56-50 win over No. 10 Marshwood in the preliminary round, ends the season 11-9.

Trailing 24-22 at halftime, South Portland took command in the third quarter with an 18-2 run that showed how the Red Riots’ versatility.

“We started running and I was getting open looks, and I was just able to hit them,” Pelletier said. “Then we started to go down low more and (our post players) just dominated.”

Playing at a higher tempo certainly did open up the floor for Pelletier, Kam Harper (six points, four assists) and Sam DePaolo (five assists) on the perimeter.

“Matt made some huge shots for us that opened things up for our bigs,” South Portland Coach Phil Conley said. “He’s a terrific shooter and he did a great job of hitting nice shots.”

That created space to operate for 6-foot-5 Jaren Muller (13 points, five rebounds), 6-4 Jordin Jackson (four points, nine rebounds, one block), and 6-5 Ruay Bol (11 points, 10 rebounds).

“We didn’t control the pace in the first half,” said Conley. “We need to push the ball up the floor, make smart decisions and control the glass, and we did.”

Cheverus came out strong, taking a 15-10 lead after the first quarter and a 24-22 edge into halftime.

Austin Boudreau led the Stags with 12 points. Jesse Matthews had 10.

“They were fronting our bigs and doing a good job on help- side defense,” Pelletier said. “That made it hard for us to lob it in.”

Cheverus was hampered when its strongest post player, 6-6 senior Zordan Holman, got into early foul trouble. Holman was on the bench much of the second quarter and for long stretches in the second half.

“They’re so big and physical,” said Cheverus Coach Dan Costigan.

“You take our big and physical guy out, it makes it tough to do some things you’d typically like to do.”

The Riots outscored the Stags 23-6 in the third to take a 45-30 lead. Pelletier then scored 14 points in the fourth quarter.

“They’re very good and they’ve got a lot of weapons,” Costigan said. “They do a nice job of coming at you and wearing you down.”