Eugenie Bouchard provided relief from a deluge of bad injury news in the women's game ahead of the Australian Open, as the Canadian won 6-2, 6-1 against Bethanie Mattek-Sands at the Hobart International on Monday.

The former No. 5 is on the comeback trail since sustaining a concussion when she fell in the dressing room during last year's U.S. Open, with the Shenzhen Open last week being her first tournament since.

Bouchard said before her first match in Hobart she had "zero expectations" for the tournament as she eases back into competitive tennis after the four-month layoff.

However she was impressive against American veteran Mattek-Sands, just as many leading Australian Open deal with injuries.

Daria Gavrilova, who teamed with Nick Kyrgios to win Australia's first Hopman Cup title in Perth last week, became the latest player to withdraw from the Sydney International on Monday, due to an abdominal injury.

"If I had a bit more time, I would be fine," Gavrilova said. "But it's just a bit sore, so it's a bit of a precaution.

"It's not great timing, but I'm not too worried because it's early days. I should be fine for Australian Open."

Defending champion and world No. 5 Petra Kvitova withdrew from the tournament on Sunday due to a stomach virus and was joined a few hours later by No. 2-seeded Agnieszka Radwanska, who cited a leg injury.

Last week, the world's four top-ranked women retired or withdrew from tournaments due to injuries: No. 1 Serena Williams (Hopman Cup/knee), second-ranked Halep (Brisbane/ankle), No. 3 Garbine Muguruza (Brisbane/foot) and fourth-ranked Maria Sharapova (Brisbane/forearm). The addition of Kvitova and Radwanska leaves the six top-ranked women all under injury clouds ahead of the Australian Open which starts Jan. 18.

Germany's Angelique Kerber, ranked 10, won her first round match in Sydney, beating Ukraine's Elona Svitolina 4-6, 6-0, 6-3, while former U.S. Open champion and local favourite Sam Stosur beat Roberta Vinci 4-6, 7-5, 7-5.

Pospisil advances over 7th seed

In men's action at the ASB Classic in Auckland, New Zealand, Canada's Vasek Pospisil ousted seventh-seed Ivo Karlovic 7-6 (4), 7-5.

American Jack Sock took only 43 minutes to beat Victor Estrella Burgos 6-0, 6-4 to claim his place in the second round. World No. 26 Sock took the first set in only 17 minutes, finishing it with his fifth ace, then won the second set with a single service break and without facing a breakpoint.

"I came out in difficult conditions today for everyone, with the wind swirling a little bit and the court fast, and I'm happy to get through."