(Photo credit: Dan Hamilton-Imagn Images)

Australian qualifier Tristan Schoolkate pulled out a 7-6 (5), 6-4 victory over Brazil's Joao Fonseca on Monday in the first round of the National Bank Open in Toronto.

It was a notable result for Schoolkate, who earned his first career victory over an opponent ranked in the Top 50. Fonseca, 18, proved himself as a rising star when he won the ATP NextGen Finals last December.

'I'm very happy with the result today. I thought I played a good match and made it pretty tricky for Joao,' Schoolkate said. 'He's obviously a very established player, he's so young ... Even when his age flashed on the (scoreboard), I was like 'Here we go.' I'm just happy with the way I played, and looking forward to the next one.'

Neither player broke serve in the first set until the tiebreaker, when Schoolkate slipped behind 4-3 before ripping off three straight points to turn the tables.

He finally broke the 49th-ranked Fonseca's serve in the third game of the second set and stayed in front from there. Schoolkate never faced break point, fired 10 aces to Fonseca's nine and won 32 of 36 first-service points (88.9 percent).

'I think these conditions (in Toronto) suit the way I play,' Schoolkate said. 'I serve big, try to get forward and make it a bit uncomfortable for the opponent, and I think that showed today.'

Czech lucky loser Dalibor Svrcina defeated Belgium's Alexander Blockx 6-4, 6-2. Svrcina was placed into the main draw when Italy's Luciano Darderi withdrew. Darderi won the Plava Laguna Croatia Open on Saturday but injured his ankle.

Frenchman Hugo Gaston was ahead 3-6, 6-4, 2-0 when Italian foe Mattia Bellucci retired.

A trio of Americans moved on to the second round: Ethan Quinn topped Japan's Yoshihito Nishioka 7-6 (1), 6-2; Mackenzie McDonald defeated Belgium's David Goffin 6-4, 6-4; and qualifier Tristan Boyer surprised Aleksandar Kovacevic 7-5, 7-6 (3) in an all-American affair.

Other winners on Monday included Yunchaokete Bu of China; Francisco Comesana of Argentina; French qualifier Adrian Mannarino; Spaniard Jaume Munar; Japanese qualifier Yosuke Watanuki; and Australians Christopher O'Connell and Aleksandar Vukic.

--Field Level Media