Australian No.1 Ashleigh Barty will continue her Australian Open preparations when she opens her Sydney International campaign against Jelena Ostapenko on Tuesday.

Barty is one of seven locals left in the tournament after Alex de Minaur and Samantha Stosur both claimed round-one victories at Sydney Olympic Park.

De Minaur will join Barty in action on Ken Rosewall Arena, where rain is predicted to wreak havoc for a second straight day after five hours of play was lost on Monday.

Countrymen Jordan Thompson is scheduled to play his second-round match against Taro Daniel, while John Millman, James Duckworth and Priscilla Hon are also scheduled to play.

Tournament organisers were scrambling to play matches late on day two, with two-time grand slam champion Garbine Muguruza finishing her win over Carla Suarez Navarro at 12.15am.

Twice Stosur had to deal with rain delays in her upset of Dominika Cibulkova, including a tricky five-minute hold-up at critical moment late in the third set.

However, the former US Open champion gutsed out a rare home win.

“I’m glad that (delay) was pretty quick in the end. I actually wasn’t too confident it was going to stop. I thought it was going to be like earlier (on Monday),” Stosur said.

“I didn’t want to have a break for too long. That point that I played to then win my service game straight up after that little break, I think, was really important and really started again strong.”

Fresh off a solid campaign in the Hopman Cup where she won two of her three matches – including a win over Muguruza – Barty is hoping to fine-tune her game ahead of Melbourne.

The world No.15 comprehensively won her most recent match against the former French Open champion in China 6-3 6-0.

De Minaur, who overcame Dusan Lajovic in a tough encounter on Monday, will have to back up strongly ahead of a showdown with American qualifier Reilly Opelka.