It was the first career meeting between Auger-Aliassime, 20, and Federer, 39, born on the same date (August 8), 19 years apart.
“Beating Roger on the grass here in Halle means a lot,” said Auger-Aliassime. “It’s a great victory that I will keep in my pocket all my life. It’s great to have this victory but of course I want to go even further here in Halle. “
Federer, the tournament’s fifth seed and eighth in the world, is considered one of the best players in tennis history, having won 20 Grand Slam singles tournaments. Auger-Aliassime considers Federer to be his tennis idol.
Federer withdrew from Roland Garros after the third round last week, saying he wanted to take care of his fitness after two knee operations.
Auger-Aliassime of Montreal won 88 percent of the points when he got his first serve in the ATP 500 circuit turf. He only faced one breaking point, the losing. Federer saved 12 of 15 break points.
The Canadian improved to 4-15 against top 10 opponents, using his powerful serve and confident groundstrokes en route to victory in one hour and 45 minutes.
“I tried to come back and put the pressure early on in the first game,” Auger-Aliassime said of his approach in the deciding set. “Being able to get that first break was really good. It made things a little easier afterwards and then going on and hitting that four ace game was the perfect way to start a third set.
“From there, I just kept going. I just tried to keep doing what I was doing well and it worked. “
Auger-Aliassime closed the match with his eighth set ace, wielding his fist a few times in celebration. The Canadian will face the German Jan-Lennard Struff or the American qualifier Marcos Giron in the quarter-finals.
Federer, who has won 103 career singles titles, took home a record 10 crowns in this tournament. He had never lost in the first or second round before at Halle, his favorite warm-up for Wimbledon.
Auger-Aliassime, meanwhile, is 0-8 in the ATP Tour final during his young career, including one final loss.
The 19-year age difference was the biggest of Federer’s 1,521 career games. He passed the 17-year eight-month-a-week difference between Federer and Denis Shapovalov of Richmond Hill, Ont.
Federer beat Shapovalov 6-2 6-4 in their only meeting of 2019 in the Masters 1000 semi-finals in Miami.
In other results, Andrey Rublev of Russia beat Australia’s Jordan Thompson 6-4, 6-4 and veteran home favorite Philipp Kohlschreiber beat Frenchman Corentin Moutet 6-4, 7-6 (4).
Meanwhile, third-seeded Bianca Andreescu of Mississauga, Ont., Lost 7-6 (2), 7-5 to France’s Alize Cornet in a second round match at the Berlin Open.
Andreescu, who won a first-round bye, was playing his first game on turf this season.