LEWISTON — The girls from Lincoln Academy were nervous. From Falmouth? Not so much.

As things turned out, both teams earned trips to the tennis state finals.

Top-seeded Falmouth extended its winning streak to 172 matches by beating No. 6 Portland 4-1 in the Class A South final Thursday at Bates College. Falmouth (15-0) will appear in the state final for the 16th time Saturday at Lewiston High against North champion Lewiston.

Lincoln (15-0), the No. 1 team in Class B South, had a tougher time but still managed to sweep third-seeded Cape Elizabeth 5-0 despite three matches being extended to a third set.

“When we pulled in here, I have five girls, their stomachs were turning,” said Lincoln Coach Charlie Scimone. “We’re never here. Cape and Greely, they’re here every year.”

Lincoln’s only straight-set victory came at second singles, where Emily Harris prevailed 6-1, 6-2 over Katie Gilman. Sandra Thelander and Anastasia Oliver of Lincoln won 6-3, 7-6 (8-6) at first doubles, and Kate Peters and Harmony Ingham rallied to win 5-7, 6-1, 6-4 at second doubles.

“We haven’t ever really been this far,” Peters said, “so the first set I was really nervous. I came into this like, ‘Omigosh, they’re going to be really good.’ I underestimated us, I think.”

At third singles, Qinyu “Fiona” Liang edged Isabel Berman of Cape Elizabeth, 6-1, 4-6, 6-1. In an all-freshmen match at first singles, Caitlin Cass of Lincoln outlasted Blair Hollyday, 3-6, 7-5, 1-0 (8).

Liang, a dorm student at the Newcastle school, was scheduled to fly back home to China on Wednesday.

Instead, buoyed by the team’s success, her teammates organized a series of bake sales to raise enough money to pay for a ticket change so Liang could remain in Maine through Saturday’s state final.

Until Thursday, Lincoln had not been involved in a three-set match. All of its previous 14 victories had resulted in scores of 5-0.

“So there was a lot of pressure we weren’t used to,” Scimone said. “For both doubles to win was incredible.”

Cape Elizabeth, which eliminated defending state champ Greely in the semifinals, finished 12-3.

In Class A, Falmouth’s strength in doubles proved too much for Portland (9-7), whose playoff victories over Thornton Academy and Cheverus avenged regular-season defeats. The Bulldogs also lost 4-1 to Falmouth in the regular season, but their lone victory Thursday came at No. 1 singles, not No. 2, where Sara Fallon of Falmouth nipped Karina Boothe, 4-6, 6-3, 1-0 (8). They played a 10-point tiebreaker to decide the third set because Falmouth already had clinched the match.

Alston Armstrong won 6-1, 6-1 at third singles.

The SMAA doubles champions, Grace Dimick and Maddy Joyce, won 6-1, 6-2 at first doubles, and Emma Cohen and Sydney Pearl won 6-2, 6-3 at second doubles.

“They’re just so good,” said Ashley Chadbourne, who played first doubles for Portland. “Their shots are so much better than what we’re playing, so it raises our competition level. It makes it more fun to play.”

Lauren Paradise of Portland spoiled the shutout with a 7-6 (3), 6-2 victory at first singles over Meredith Kelley of Falmouth.

“We knew they were getting better as the season went along,” Falmouth Coach Bill Goodspeed said. “Even though we won earlier in the year, we weren’t expecting a 4-1 win. We respect them.”

In the Class C South final, No. 2 Maranacook edged top-seeded Carrabec 3-2 when Emma Wadsworth won 1-6, 6-3, 6-2 at second singles. Maranacook (13-2) swept the singles matches and Carrabec (12-1) took the doubles.