WATERVILLE — Allie Anich was feeling the heat. And not just from the 85-degree temperatures beating down on North Street Recreation Area for much of Wednesday.

The senior’s top-seeded Waterville girls tennis team was on the verge of letting a 2-0 lead over No. 5 Ellsworth in the Class B North semifinals slip away after the visiting Eagles won at No. 1 singles and were about to win at No 3 while Anich and her opponent, Brianna Kane, went to a tiebreaker.

But Anich, who had battled Kane back-and-forth for nearly 3 1/2 hours, won the extra session to take an epic 4-6, 6-4, 7-6 (7-1) victory that gave the Panthers a 3-2 win.

Waterville plays for the regional title Saturday against an opponent to be determined.

“It feels very amazing,”  said Anich, who added Wednesday’s win was among the longest matches she has ever played. “It feels great to play a long game and have a good outcome.

“As soon as I watched first singles come off, I look over at the stands and they look at me and go …” She shook her head. “I knew it was either second singles or third singles that was going to win it.”

Anich trailed Kane 4-5 in the third and deciding set before she rallied to take a 6-5 lead. Kane tied the match to force the tiebreaker.

“This was as much of a test as you could possibly have,” Waterville co-coach Jon Hart said. “Both teams could have won 4-1, and it was 3-2, and you didn’t know what was going to happen until that very last point.”

The hot, cloudless day, interrupted by the occasional breeze, tested everyone’s mettle. After Waterville’s Arian Gilman tied her No. 2 singles match with Miah Coffin at one set apiece, a tired Gilman needed a break on the sideline, where Hart cooled her off with ice water, a cold towel and a slice of watermelon before she returned to the court, where her match also went to a tiebreaker. Coffin prevailed 7-5, 4-6 7-6 (7-0), just before Anich’s victory, by which time the temps had dipped with the sun.

“My first two sets, I would say I was struggling in the weather,” Anich said. “But when the degrees went down it definitely helped. We were told to drink a lot of water today.”

Waterville’s match was originally scheduled for Thursday, but moved up a day because Thursday’s forecast called for temps in the low 90s. This meant the Panthers had to play for a second straight day following Tuesday’s 5-0 quarterfinal win over Winslow.

“We’re gonna be gassed, but we’ll recover,” Hart said.

After Ellsworth’s Kane dropped the second set to Anich, she and Ellsworth coach Brian Higgins retreated to the shade, under the rec area’s nearby wooden canopy, for their 5-minute between-sets break.

“We surprised ourselves,” said Higgins, who has coached the program since it debuted in 1980. “Everybody played the best they could have played today.”

The Panthers dropped the first set in four of their five matches but went on to sweep the doubles events, with the No. 1 duo of Fatima Sheikh and Piper Hamilton defeating Kahlan Keene and Emily Gagnon, 6-4, 6-2, and the No. 2 pair of Skylah Talon and Taylor Doane outlasting Elizabeth Frost and Whitney Clarke, 2-6, 6-4, 6-1.

“We had to fight back. They had to fight back,” Hart said. “The kids from both teams showed so much heart today, I can’t even describe it. It’s unbelievable.”

Karin Zimba, Waterville’s No. 1, fell to Ellsworth’s Megan Jordan 3-6, 1-6.