Serena Williams beats Flavia Pennetta at Rogers Cup

But the 33-year-old American, a three-time champion on the Toronto hard courts, eventually found her rhythm to get her U.S. Open buildup off to a winning start.

“I think she can be beat but it’s really tough”, said Romania’s Halep.

According to a Reuters report, Germany’s Sabine Lisicki scored a win over Venus Williams when the match resumed.

“She was just playing so well in the first set and a half; she just started moving me and hitting really hard and I just had to get through that”, explained Williams.

Fans who waited out the rain tried to encourage Williams during her struggles. “You have to be ready and fight for every point, and I’m very pleased with my performance”.

“It is all the time robust after an extended rain delay, you do not know in case you are ever going to get onto the courtroom and with a troublesome match towards Venus”, stated Lisicki.

Instead of her usual rain-delay ritual of ping-pong, the 24th-ranked player in the world played a game of UNO.

Williams, trailing 3-0, had a chance to break back but could not convert as Lisicki held to forge further ahead.

“It was definitely good for me to have a match like this, to play a good player like her, especially since I haven’t played a match on hard court since early April”.

Rain ensured only one other match finished, with Flavia Pennetta breezing past Canadian wildcard Gabriela Dabrowski 6-4 6-1.

World No. 1 Serena Williams, who has 14 more Grand Slam titles than her sister, faces Pennetta in second-round action Tuesday afternoon.

Pennetta’s reward for her victory is a second round clash with top-seed Serena Williams on Tuesday.

Canadian star Eugenie Bouchard of Westmount, Que., was set to face Switzerland’s Belinda Bencic in her first-round match on centre court at 7 p.m. ET.

Richmond Hill’s Carol Zhao played American Madison Brengle in the afternoon, while Montreal’s Francoise Abanda will play 16th-seeded Andrea Petkovic of Germany after Bouchard’s match.