Thornton Academy girls’ basketball coach Eric Marston, center, talks to his team at the start of preseason practice. The Trojans open the playoffs with a Class AA South quarterfinal against South Portland, a team Thornton beat twice this season. But Marston says his team is not about to take the Red Riots lightly. Ben McCanna/Staff Photographer

You have to go back to the 2001-02 high school basketball tournament to find one with as many preliminary-round games as this year.

Twenty years ago it was because the Maine Principals’ Association was in the second season of a two-year open tournament experiment. This season, with many teams unable to complete a full regular season because of the coronavirus pandemic, it’s an open tournament again.

More teams in the field means there could be more upsets, a factor higher-seeded teams are well aware of in the girls’ tournament.

“It’s always interesting, because we don’t play half the teams in the tournament,” said Tom Robinson, North Yarmouth Academy’s coach. At 14-2, NYA is the No. 3 seed in Class C South, and will host No. 14 Monmouth (3-10) in a prelim game Tuesday. “You’re never 100 percent confident with a prelim game. We’re glad it’s home.”

This year’s high school basketball tournament is the first since 2020. The 2021 tournament was canceled because of the pandemic.

While girls’ basketball teams in Classes A through D play preliminary-round games over the next few days to fill out the quarterfinal fields at their regional tournaments, Class AA schools open quarterfinal play Tuesday night at the higher-seeded school.

One of the intriguing quarterfinal matchups could be in the South when No. 3 Thornton Academy (13-5) hosts No. 6 South Portland (5-13) at 6 p.m. Thursday. Despite the disparity in their records, Thornton Coach Eric Marston expects a close game. The Trojans beat South Portland twice in the regular season, 68-61 on Dec. 23, and 67-54 on Jan. 22.

“The wins didn’t come easy by any means. South Portland is not a team we’re taking lightly,” Marston said.

In AA North, No. 5 Windham (11-7) and No. 4 Bangor (12-6) meet in Bangor at 6 p.m. Wednesday after splitting a pair of regular-season games. Bangor took the first contest 54-26 and the Eagles won the rematch, 46-40.

With the top four teams in Class A South receiving byes to the quarterfinals, No. 5 Gray-New Gloucester (12-6) is the only team with a winning record playing a preliminary-round game. The Patriots host No. 12 Kennebunk (0-15) at 6 p.m. Wednesday.

No. 10 Westbrook (5-13) is one of the teams that in a typical season would not be in the tournament. With Wednesday’s game at No. 7 Marshwood (7-10), Coach Diana Manduca is hoping, win or lose, the game will be a learning experience for her young Blue Blazes. Of the 13 players on Westbrook’s varsity roster, seven are freshmen.

“I think it’s exciting they get to feel what that playoff experience is like,” Manduca said. “They’ll get a taste of that atmosphere and if we win they can get a taste of what it’s like on the Expo floor.”

When Westbrook beat Marshwood 45-43 on Dec. 28, the Blue Blazes limited their turnovers. In the rematch last Thursday, a 54-40 Marshwood win, Westbrook turned the ball over 20-plus times, Manduca said.

Marshwood enters the tournament as one of the hotter teams in Class A South. After winning just one of their first nine games, the Hawks turned a corner. Led by senior forwards Sophie Mitchell and Jasmine Aloisio, the Hawks won six of their final eight. Marshwood played just eight games last season, Coach Angie Littlefield said, and it took some time for the players to gel on the court.

“It took us a while to just play together,” Littlefield said. “I think we played up to our potential (in the second half of the season).”

In Class B South, only top seed Wells (17-1) and No. 2 Oceanside (16-0) earned byes to the quarterfinals. None of the six preliminary games feature two teams with a winning record.

Junior point guard Angel Huntsman will lead the way for North Yarmouth Academy in the Class C South playoffs. Derek Davis/Staff Photographer

NYA can lay claim to being the most-tested team in the Class C South field. The Tigers’ two losses came to teams in higher classes, Wells, the top seed in Class B South, and Brunswick (16-2), the No. 1 seed in Class A South. Brunswick defeated NYA 53-50 just over a week ago as both teams scrambled to find games and fill out their schedule.

“We did a good job against Brunswick. It was a good learning experience for us,” said Robinson, who added his team has five players averaging at least eight points per game.

A win over Monmouth on Tuesday would give NYA a week off before the quarterfinals at the Augusta Civic Center next Tuesday. This comes after playing five games in 10 days to complete the regular season.

“We were hard-pressed to get all the games in, then you have a week layoff, which isn’t ideal,” Robinson said.

The lone preliminary-round game in Class D South features a pair of island schools with No. 9 Vinalhaven (0-9) playing at No. 8 North Haven (3-6).