Birthday Boy Stefanos Tsitsipas Tops Karen Khachanov 6-2, 6-3, in Toronto

Stefanos Tsitsipas celebrated his 23rd birthday by beating Karen Khachanov 6-2, 6-3 to advance to the National Bank Open quarterfinals. (More Sports News)

The crowd serenaded the No. 3 seed from Greece with a rendition of “Happy Birthday” as he was presented with a white sheet cake decked out with fresh fruit.

"One of the best feelings you can experience on a tennis court,” said Tsitsipas, who is ranked No. 3 and lost the French Open final to Novak Djokovic in five sets.

Tsitsipas dominated his Russian opponent, saving both his break points and winning 74% of his service points.

He will face sixth-seeded Casper Ruud of Norway in the quarterfinals Friday. They met at the Madrid Open in May, with Ruud winning in straight sets in the round of 16.

"I'm looking for a change, looking for a switch-up this time," Tsitsipas said.

Ruud beat Dusan Lajovic of Serbia 6-4, 6-3.

Top-seeded Daniil Medvedev of Russia also advanced, beating Australia’s James Duckworth 6-2, 6-4 in a night match.

"I managed to get a few tight games, managed to get ahead," Medvedev said. "I think he lost his rhythm a little bit, so that was well my fault, also,”

Medvedev will face seventh-seeded Hubert Hurkacz of Poland. Hurkacz edged Nikoloz Basilashvili of Georgia 6-7 (7), 6-4, 6-4.

Fourth-seeded John Isner of the United States beat Russia's Andrey Rublev 7-5 7-6 (5). Isner will face 11th-seeded Gael Monfils of France, a 6-1, 7-6 (2) winner over American Frances Tiafoe

American Reilly Opelka beat Lloyd Harris of South Africa 4-6, 7-6 (6), 7-6 (4). Opelka will play 10th-seeded Roberto Bautista Agut of Spain. Bautista Agut overcame three match points to beat eighth-seeded Diego Schwartzman of Argentina 6-3, 3-6, 7-5. (AP)