A few close officials’ calls went against No. 1 Thornton Academy in the final seconds and South Portland took advantage to take the lead and the 39-36 win in Tuesday’s Class AA South boys’ basketball regional semifinal at the Cross Insurance Arena.

No. 4 South Portland (11-9) advances to the regional final at 9 p.m. Friday against No. 3 Massabesic (16-4) at Cross Insurance Arena.

Thornton (16-3) led by a point and Corey Hart appeared to be free for a breakaway layup. South Portland’s Jack Fiorini came hustling from behind to block the shot.

Based on Hart’s reaction, he believed Fiorini’s block came after the ball hit the backboard. If that was the case, goaltending would have been called and the basket would have counted.

Asked if he thought Hart’s shot hit the backboard, Thornton Coach Robert Davies said, “Yes.”

Television replays indicated it was a good block.

“Big-time players make big-time plays in big games,” South Portland Coach Kevin Millington said of Fiorini’s block with 32 seconds left.

With 11.2 seconds left, Fiorini was fouled by John Fogg inside. Fogg had a lot of the ball and showed a bit of displeasure with his body language. He was quickly given a technical foul, too.

“I asked my player what he said and he said he didn’t say anything,” Davies said. “He had an emotional reaction. I don’t know if he said anything.”

The fouls gave South Portland four free throws and possession of the ball. Fiorini made both free throws for the lead. Matt Pelletier added one of the two technical foul shots. After the inbound, Pelletier was fouled and made one more free throw with 6.5 seconds left, before missing the second.

Thornton rebounded Pelletier’s miss. A long outlet pass found Benjamin Lambert open for a 3-point look on the left baseline. Lambert’s shot rimmed out at the buzzer.

Jack Tilley scored 17 points for Thornton. Fiorini had 13, 10 in the second half.

A first half of stagnant offense ended with TA holding a 14-13 lead.

Neither team led by more than three points in the second half. Tilley had a six-point surge in a brief flurry that turned a 31-28 deficit into a 34-31 lead with 3:54 to play.

Ruay Bol and Tilley then traded baskets, the latter coming with 3:10 to play.

It was Thornton’s final score. Jordin Jackson cut the lead to one when he bulled to the hole for one of his four baskets.

“We didn’t play very well and to be honest I didn’t think they played very well,” Davies said. “It was a very slow game which was probably what they wanted.”