New York, NY, USA, 5 September 2015 | tennis.com.au/AAP

This is where the going gets tougher.

Bernard Tomic and Sam Stosur, Australia’s top ranked male and female players and the nation’s two seeded contenders, face higher seeds on Saturday in the third round of the US Open.

Tomic, the men’s No.24 seed, takes on 12th seed Richard Gasquet – who outlasted another Aussie in Thanasi Kokkinakis in the first round – while women’s 22nd seed Stosur faces Sara Errani, the Italian No.16 seed who has won their past two matches.

They will play back-to-back in the first two matches of Saturday’s schedule on Grandstand.

> view the full US Open Day 6 order of play

Tomic believes he has the arsenal and energy to take out the Frenchman and make the second week.

“I spoke to him in the locker room. He was, as well, very tired. He was feeling some problems out there. Everyone is feeling problems,” Tomic said.

“I think my record is 4-1 (in Gasquet’s favour). I beat him in a very important one, which is Wimbledon, third round, 2013.

“Every match we had in the past was very close. I’ve learned a lot when I played him. He’s an amazing player. He’s not easy to play.

“I have to take each match that I played against him and use it for this third-round match.”

The record is actually 5-1 to Gasquet, with he and Tomic splitting meetings at Grand Slam tournaments.

For Stosur, she leads Errani 5-2 in their career head-to-head, but lost the two most recent and important meetings – both in 2012, at Roland Garros and the WTA Finals.

“We have played quite a few times, and the last couple of times she’s beaten me. There have been some pretty big matches,” Stosur said.

“But this is different – again, another situation and a court that I feel like I match up well against her on. I think we have actually played on Armstrong years ago.

“Even though I think all that, it’s still going to be a tough match playing her given our history and some of the long battles we have had.

“I will look forward to that challenge.”

Aussies in action on Day 6

Men’s singles – third round

[24] Bernard Tomic v [12] Richard Gasquet (FRA) – Grandstand, first match

Women’s singles – third round

[22] Sam Stosur v [16] Sara Errani (ITA) – Grandstand, second match