Jessica Pegula said she would allow herself to enjoy a cold beer after beating world number one Iga Swiatek of Poland in the Canadian Open semi-final on Saturday, but the celebration would be put on ice until the tournament is completed.

American world number three Pegula, playing in her third consecutive Canadian Open semi-final, broke Swiatek's serve 11 times and managed her way through the big moments of the match better than the four-time Grand Slam winner.

"She always makes it tough but of course it's incredibly rewarding to beat the number one player in the world, and I am sure that will give me a lot of confidence going into tomorrow and the next couple weeks," Pegula said after defeating Swiatek 6-2, 6-7(4), 6-4 on Saturday to reach the Canadian Open final in Montreal.

Swiatek won the first eight points of the third set to build a 2-0 lead, but Pegula kept cool and twice came back from a break down en route to securing one of the biggest wins of her career.

Pegula endured a bizarre moment in the second set tiebreak when the song "Cotton-Eye Joe" began playing on the speakers in the middle of a rally.

The musical mishap threw the 29-year-old off her game as she lost the set, but she recovered in the next to close out the win.

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

"Yeah, it was a bummer because I hit a really good lob and she barely got it, and I had a really good play on the ball, and she was kind of out of position from the lob that I hit."

(With input from Reuters)