MONTREAL -- South Korea's Hyeon Chung upset Feliciano Lopez of Spain 6-1, 4-6, 7-6(3) on Tuesday in first-round action at the Rogers Cup.

Chung, ranked No. 56 in the world, took advantage of several mistakes made by the 28th-ranked Lopez, including eight double faults, to win the two hour 16 minute match.

Lopez is now 10-12 in his career at the Rogers Cup.

The opening match on centre court at Uniprix Stadium was supposed to feature 10th-ranked Tomas Berdych but he pulled out with a rib injury. Berdych's withdrawal ended a streak of 12 consecutive appearances in Canada for the Czech player.

"I am sorry I have to apologize (to) all my Montreal fans," tweeted Berdych. "I couldn't play, because of my rib disfunction I need to get well to go to office soon!!"

No. 85 Ernesto Escobedo took his spot and upset 63rd-ranked Nikoloz Basilashvili in straight sets 7-6(4), 6-4.

Borna Coric easily defeated Mikhail Youzhny 6-2, 6-4 to set up a meeting with Rafael Nadal in the second round.

Italy's Paolo Lorenzo downed American Frances Tiafoe 7-6(3), 0-6, 6-2.

Denis Shapovalov of Richmond Hill, Ont., ranked No. 143, plays 64th-ranked Rogerio Dutra Silva of Brazil later in the afternoon. Shapovalov, who was granted a wild card spot in the tournament, is the only Canadian in singles action on Tuesday.

Milos Raonic from Thornhill, Ont., was initially scheduled to play his opening match on Tuesday but a minor injury forced him to postpone it to Wednesday. He faces France's Adrian Mannarino.