Montreal's Gabriel Diallo needed three hours and 19 minutes to beat Damir Dzumhur of Bosnia and Herzegovina.

The 31st-seeded Diallo, who committed 71 unforced errors but had 17 aces, chalked up a 7-6 (4), 4-6, 7-5, 7-5 win in his opening-round men's singles match.

Diallo won 74 per cent of his points on first serve and only double faulted twice. He saved two of five break points and won three of nine break points. He also earned 34 per cent of his points on returns.

Diallo had 59 winners while Dzumhur had 22 to go with 40 unforced errors.

Diallo will play Jaume Munar of Spain in the next round. Munar defeated Jaime Faria of Portugal 6-0, 6-3, 5-7, 6-2 on Monday.