BRISBANE, Australia — Canadian young gun Denis Shapovalov edged world No. 6 Stefanos Tsitsipas in his country's clean sweep against Greece on the first day of the inaugural ATP Cup on Friday.

The 20-year-old Shapovalov downed the world No. 6 7-6 (8-6), 7-6 (7/4) in Brisbane to give Canada an unassailable 2-0 lead after Felix Auger-Aliassime thrashed Michail Pervolarakis 6-1, 6-3.

The two then combined in the doubles to beat Pervolarakis and Tsitsipas 6-2, 6-3.

"It was definitely a great start to the event — these boys played awesome," Canadian captain Adriano Fuorivia said. "It's easy to support them when they're playing like that."

Shapovalov's left-handed serve was working beautifully in his match against Tsitsipas, who faltered at key moments in both tiebreaks.

Tsitsipas, 21, had a superb end to 2019, winning the ATP Finals in his tournament debut and reaching a career-high world ranking of five.

He went into the match as slight favorite over the Canadian, ranked nine places below him.

Both players were relatively untroubled on serve but Shapovalov made the clutch points in the two tie-breakers to take the match in just over two hours.

"It's definitely a huge win for me," Shapovalov said.

"Obviously, he had an unbelievable end to the season and he's definitely one of the top players in the world right now so to beat a guy like this first match of the year, it's really special for me."

Tsitsipas conceded he had returned poorly, which proved the difference.

"I don't know whether it was because he was a lefty. I don't really usually have this much trouble playing lefties, but today I think he was serving well — that was pretty much it," Tsitsipas said.

"His serve was better than mine and a few points in the tiebreak, I didn't work out what I had to do and I didn't have a clear picture of how I have to play."

World No. 21 Auger-Aliassime was far too strong for Pervolarakis, 466 places further down the ATP rankings.

The Canadian cruised through the first set before Pervolarakis — playing his first match on the main ATP tour — could adjust to the pace, but the 19-year-old was never in trouble and wrapped up the match in 69 minutes.

"I was happy that overall in the match I had a great first set, couldn't ask for any better, and I was able to be solid in the second," Auger-Aliassime said. — AFP