World number one Jannik Sinner opened his defence of the Canadian Open with a straight sets win over Borna Coric in Montreal.

Italian Sinner had missed the Paris Olympics with tonsillitis, but showed no signs of any lingering issues as he coasted to a 6-2 6-4 win over Croatian Coric in just over an hour and a half.

Australian Open champion Sinner – who paired up with British number one Jack Draper in the doubles, making it through to the quarter-finals – will face Alejandro Tabilo in the third round after the Chilean later beat Lorenzo Sonego 6-4 6-2.

Elsewhere on Thursday, Russian world number five Daniil Medvedev suffered an early exit after a surprise defeat to Alejandro Davidovich Fokina, the Spaniard coming through in three sets 6-4 1-6 6-2.

Kei Nishikori earned his first top 20 win since 2021 after he upset world number 11 Stefanos Tsitsipas 6-4 6-4.

American qualifier Brandon Nakashima completed a 6-2 6-7 (5) 6-1 win over countryman Tommy Paul, who missed the chance to close up on Tsitsipas in the Race To Turin.

World number four Alexander Zverev comfortably saw off Australian Jordan Thompson 6-1 6-1 to reach the third round, while Casper Ruud, Holger Rune, Andrey Rublev and Grigor Dimitrov also progressed.

Meanwhile, Olympic champion Novak Djokovic has withdrawn from next week's Cincinnati Open, the tournament has announced.

The Serbian, who won the event last year, has been managing a torn meniscus in his right knee, which needed surgery ahead of Wimbledon.

Cincinnati Open tournament director Bob Moran said in a statement: "We certainly understand that it is a quick turnaround from his Olympic triumph to come to Cincinnati.

"His title run here last year was so memorable. We are eager to see him on court again soon."