Joao Fonseca will face defending Canadian Open champion Ben Shelton for a quarter-final spot in Montreal following his straight-sets victory over Casper Ruud. 

Fonseca was able to overcome a slow start to claim a 7-6 (8-6) 6-3 win in just under two hours to reach his third career round of 16 at an ATP Masters 1000 event, with all of those runs having come in 2026.

The 19-year-old was, however, put on the back foot early on. Fonseca had to save five break points in the opening four games before Ruud eventually found a breakthrough.

But Fonseca was able to immediately claw back a break of serve and level things up at 4-4, before going on to win the tie-break at the third time of asking. 

Fonseca found his groove from there, reeling off the first three games in double-quick time while also missing a chance to go 4-0 in front. 

Ruud was able to regain his composure, but the damage had already been done as Fonseca confirmed his progression by following up his huge serve with a forehand winner. 

"These are the matches that you're most proud of, because you find a way to solve the problem," said Fonseca. "I solved it. It's a tough opponent, and I'm very proud of myself."

Made in Brazil

Fonseca makes it four Top 20 wins with a statement victory over Ruud!@OBNmontreal | #NBO26 pic.twitter.com/O1RCNGMM2b

— ATP Tour (@atptour) August 8, 2026

Fonseca will be joined in the last 16 in Montreal by Jakub Mensik after the 13th seed cruised past Terence Atmane in straight sets earlier in the day. 

Mensik made it through to his second ATP Masters 1000 fourth round of the season following his 7-5 6-4 win in one hour and 41 minutes. 

But there was no route for Tommy Paul into the next round after he lost an all-American clash with 12th seed Learner Tien. 

Tien came out on top 6-3 6-2, with Argentina's Thiago Agustin Tirante his next opponent. 

Fonseca finding his feet after Wimbledon setback

Playing in his first tournament since a shock third-round exit to qualifier Roman Safiullin at Wimbledon, Fonseca claimed his seventh career ATP top 20 win on a hard court. 

Fonseca's triumph also saw him defeat multiple ATP Masters 1000 champions at a single such event for the first time in his career, following his opening win over Stefanos Tsitsipas, and he is not the only rising star who has impressed in Montreal. 

Rafael Jodar, who beat Lorenzo Musetti in straight sets, has also been one of the standout players. And, coupled with Fonseca's win, it is the first time since Tsitsipas and Denis Shapovalov in 2018 that two teenagers have reached the round of 16 at the Canadian Open. 

Mensik is also a youngster in form, as he flies the flag for Czechia alongside Jiri Lehecka. It is the first time two male players from the nation have made the last 16 at the Canadian Open since Tomas Berdych and Radek Stepanek a decade ago.