Canada's Felix Auger-Aliassime won the first-ever ATP Cup match on Thursday. Teammate Denis Shapovalov followed that up with an impressive victory of his own.
Auger-Aliassime, 19, defeated Greece's Michail Pervolarakis 6-1, 6-3 to open the tournament's inaugural edition in Australia.
The 21st-ranked Montreal native fired five aces while winning 85 per cent of his first-serve points against his Greek foe, ranked 487th.
After Auger-Aliassime dusted aside Pervolarakis, Shapovalov took down world No. 6 Stefanos Tsitsipas in straight sets, with both ending in tiebreaks.
WATCH | Auger-Aliassime, Shapovalov make history at ATP Cup:
Interrupted by a weather delay, the 20-year-old Canadian, ranked No. 15, kept his composure to upend Tsitsipas 7-6(6), 7-6(4). Shapovalov now has a 3-1 lead in career meetings over ATP Finals champion Tsitsipas, who was unable to convert his breakpoint chances in the seventh and 11th games of the second set and then had a double-fault on match point.
"It's always amazing to be part of the team and have kind of a team feeling — it's pretty rare on the tour, so I definitely love it and I always feel like I thrive off that atmosphere," Shapovalov said., "So, yeah, I'm really happy, happy with the result today."
That victory clinched Canada's win in the best-of-three against Greece, with a doubles match between the quartet of combatants still to be played.
"It's definitely a huge win for me. Obviously, he had an unbelievable end to the season and he's definitely one of the top players in the world right now," Shapovalov said. "He's got a great game. So to beat a guy like this first match of the year, it's really special for me. It means a lot."
Next up, the Canadians take on host Australia on Saturday at 7 p.m. ET.
Australia was playing Germany in the other Group F match Friday night in Brisbane.
The United States took the first singles off Norway in Group D when Taylor Fritz beat Viktor Durasovic 6-2, 6-2 in Perth. John Isner was playing Casper Ruud in the second singles encounter.
Belgium took a 1-0 lead in the best-of-three match against Moldova, the last team to qualify, when Steve Darcis held off Alexander Cozbinov 6-4, 6-7 (4), 7-5 in Sydney. David Goffin was playing Radu Albot in the second singles.
The winners from each of the six groups and the two best runners-up will advance to the quarter-finals, which will start in Sydney on Jan. 9.
The ATP Cup sees 24 nations contesting in Perth, Brisbane and Sydney over 10 days for the first time and will give the top men's players a solid platform to prepare for the Australian Open.
To accommodate the $15 million US ATP Cup, which also offers 750 ranking points, the year's first Grand Slam — the Australian Open — has been pushed back from its usual mid-month start by a week and will kick off at Melbourne Park on Jan. 20.