MONTREAL -- Jessica Pegula could not get her serve going on Saturday. Luckily for her, neither could her opponent.

The American broke world No. 1 Iga Swiatek of Poland 11 times en route to a 6-2, (4) 6-7, 6-4 victory in an unusual semifinal where serving appeared to be a major disadvantage at the National Bank Open.

"I was getting frustrated that I wasn't holding," said Pegula, who was broken eight times herself. "But then at the same time I knew she was having trouble holding as well.

"I was just like, I know I'll get more chances if I can just ... hold. Basically, it was whoever could kind of consolidate the break."

Pegula, the tournament's fourth seed, advanced to Sunday's final where she'll face the winner of the semifinal match between third-seeded Elena Rybakina of Kazakhstan and 15th-seeded Liudmila Samsonova of Russia.

Pegula will have to wait until Sunday afternoon to learn who her opponent will be as play was called off in Montreal due to poor weather conditions. The semifinal is scheduled for 1:30 p.m. ET, and the final is expected to be played later in the evening.

It's Pegula's first time in the NBO final after falling out in the semis the last two years.

Up 5-4 in the third set, Pegula broke Swiatek a final time after the top seed hit two shots long to take the win in two hours 30 minutes on a sunny afternoon at IGA Stadium.

The two opponents only won 11 of 30 service games combined.

Pegula even had a chance to end the match much earlier, up 5-4 in the second set and serving, but Swiatek broke her serve to stay alive and eventually win the set in a tiebreak.

So how does one explain why the players struggled so much on serve? Pegula couldn't say for sure, but wondered if it might have something to do with new tennis balls.

WTA players are testing out Wilson extra duty balls -- instead of regular duty -- for the first time on hard courts this week, through next week and into the U.S. Open in late August/early September.

"I don't know why this week all of us seem to be really having trouble, even girls that are considered the best servers on tour. It's weird," said Pegula. "It feels like the conditions, it's flying a little bit, it's swirling. I know it's also the first week we're playing with the Wilson extra duty balls.

"They're a little bit heavier, so they're not quite coming off the racket as well. Maybe we're not used to it."

Swiatek -- the No. 1 for 71 weeks running -- made an uncharacteristic number of errors throughout the match, including four double faults.

"I kind of knew what I had to do to push her. Sometimes I could do that, sometimes I was making more mistakes -- and I think that was the difference," said Swiatek. "But I tried to play aggressively for the whole match."

Pegula, who beat doubles teammate Coco Gauff on Friday, advances to her second WTA final this year.

The 29-year-old can bring her career title count to three with a win Sunday. She hasn't won a tournament so far this season.

Whether she plays Samsonova or Rybakina -- who played until 3 a.m. local time Saturday morning -- Pegula says her approach will be the same.

"Two similar players, serve big, hit big, like to really go after their shots, both really tall, physical girls," she said. "Whoever wins I feel like it's a very similar game plan, trying to take away their serve and then do my best to just play my game."

Serving was not an advantage from the beginning on Saturday. Pegula broke three times and Swiatek broke twice to start the match, which was filled with numerous long rallies.

Pegula, who did much of her damage with her forehand, finally broke through in the sixth game, scoring four straight points to secure the first hold of the match and take a 4-2 lead.

And Pegula wasn't done there. She broke once more as Swiatek continued making unforced errors while serving, despite getting 86 per cent of her first serves in play.

The American then served to take the set handily, sealing it with an ace.

Swiatek opened the second set strong, finally winning her first service game of the match.

Then the pattern from the first set continued as both players struggled gaining momentum on serve.

Swiatek and Pegula both broke each other twice consecutively before the American held to tie the set 3-3.

Then the players returned to breaking each other until Swiatek and Pegula both held to tie it 6-6 before the tiebreak, where "Cotton Eye Joe" by Swedish music group Rednex started blaring from the stadium's speakers in the middle of a point.

"I just thought it was funny. I've never had that happen, let alone Cotton Eye Joe," said Pegula. "I was just like 'is this really happening right now?' Like, of all the songs. It was just like 'what is going on?"'

Pegula lost the ensuing five points and the tiebreak before falling behind 2-0 to Swiatek early in the third, but climbed back knowing she'd always have a chance to break back the way the match was going.

This report by The Canadian Press was first published Aug. 12, 2023.