Sydney NSW, Australia, 9 January 2018 | AAP

Sam Stosur has enjoyed her first win of the Australian summer to reach the second round of the Sydney International.

The Australian No.3 rebounded from a first-round exit at last week’s Brisbane International with a gritty 4-6 7-5 6-3 win on Tuesday over rising German Carina Witthoeft.

Stosur next faces the winner of Tuesday’s all-Australian clash between Daria Gavrilova and Olivia Rogowska for a place in the quarterfinals. The host nation is guaranteed two quarterfinalists, with the winner of the Ash Barty-Ellen Perez clash also progressing to the last eight.

Fans crammed in to Court 3 and stood six deep outside to get a look at the former US Open champion and world No.4.

Stosur didn’t disappoint, digging deep late in the second set – when she stood only two points from defeat – to finally prevail after two hours and 21 minutes.

The victory will serve as a much-needed confidence booster ahead of the Australian Open starting on Monday in Melbourne.

“Even though she lost the last round of quallies, she played three matches,” Stosur said of Witthoeft, a lucky loser.

“We were close in rankings. I think anyone who is pretty much main draw or in qualifying here, they are very good players. The field is so strong.

“I certainly was aware I was going to be in for a tough battle today. I felt like as the match went on I probably played better and better, started timing the ball better. Really kind of just got used to everything and started, I felt, to play pretty well. I felt my serve was really good today.

“In those moments where I really needed to knuckle down and really stick to it and make something happen toward the end there, try and serve it out, I think I did a good job. All in all, very happy.”