It was a 23rd birthday Stefanos Tsitsipas isn't likely to forget any time soon.

The No. 3 seed at the National Bank Open in Toronto celebrated the milestone Thursday with a 6-2, 6-3 win over Russia's Karen Khachanov to advance to the quarterfinals.

The crowd wasn't about to let Tsitsipas' big day fade into the background after the win, serenading him with “Happy Birthday” as he was presented with a white sheet cake decked out with fresh fruit.

“The best feeling. One of the best feelings you can experience on a tennis court,” Tsitsipas, the world No. 3, said after the match. “I'm glad they remembered.”

The Greek tennis pro was dominant against Khachanov, saving both of his break points and winning 74 per cent of his total service points.

He'll face Casper Ruud of Norway in the quarterfinals on Friday. The pair met at the Madrid Open in May, with Ruud taking a straight-sets victory in the round of 16.

“I'm looking forward to that battle,” Tsitsipas said. “We have played each other in the past, (he's) not an easy guy to play against. I'm looking for a change, looking for a switch-up this time.”

AT the women's tournament in Montreal, Canadian Rebecca Marino's stunning run came to an end Thursday with a 6-1, 6-3 loss to No. 1 seed Aryna Sabalenka of Belarus.

The wild card entry from Vancouver fell behind early with Sabalenka, the world No. 3, saving four break points to cruise to a 5-0 lead in the first set.

Marino came out strong in the second set with a pair of aces and held her serve through the first six games. But the 30-year-old from Vancouver struggled with break points, going 0-for-5 across the 59-minute match.

Sabalenka will face No. 8 seed Aryna Azarenka, also of Belarus, in the quarterfinals on Friday.

Marino, ranked 220th in the world, made it to the round of 16 by upsetting No. 16 seed Madison Keys and Spain's Paula Badosa, No. 31 in the world rankings.

Hours after their singles bout, Sabalenka and Marino met again in doubles action Thursday. Sabalenka and Elise Mertens of Germany ousted Marino and Montreal's Leylah Annie Fernandez with a 7-6(4), 6-2 win.

Fellow Canadian Bianca Andreescu, the tournament's No. 2 seed, was set to face Ons Jabeur of Tunisia in singles action later on Thursday.

Andreescu is looking to defend her 2019 title at the tournament formerly known as the Rogers Cup. The event was not held in 2020 due to the COVID-19 pandemic.

This report by The Canadian Press was first published Aug. 12, 2021.