Melbourne VIC, Australia, 17 January 2014 | AAP

Resurgent Casey Dellacqua has equalled her best-ever grand slam performance after storming into the fourth round of the Australian Open at Melbourne Park.

Dellacqua was dominant throughout her third-round encounter with former Australian Open and US Open semi-finalist Zheng Jie, winning 6-2 6-4 to set up a round of 16 clash with Canada’s Eugenie Bouchard.

The West Australian left-hander has only dropped 13 games in her first three matches and will fancy her chances of clocking up another victory against Bouchard, the No.30 seed who saw off the challenge of American Lauren Davis 6-2 6-2 earlier in the day.

Dellacqua raced through the first set in 33 minutes and looked set for a straightforward victory when she broke Zheng’s serve again in the opening game of the second stanza.

But the Chinese player got back on level terms.

Zheng took a five-minute medical timeout to be treated for heat stress after the seventh game and it appeared to briefly rattle Dellacqua, who dropped her serve immediately after the resumption.

But the 28-year-old was able to break straight back and then serve the match out.

The only other time Dellacqua has reached the fourth round of a major was at the 2008 Australian Open.

She underwent major shoulder surgery in the following year.

Dellacqua says is now in career-best form and fitness.

“It feels pretty good,” said Dellacqua.

“I didn’t know if I’d ever be back in the fourth round of an Australian Open, or any grand slam.

“Every athlete has their journey, mine was a couple of injuries, a couple of years of hard work and now I’m back in the fourth round and it feels awesome.

“I’m playing really good and it’s just about keeping the roll going and keeping the body healthy and we’ll see what happens.”

Dellacqua would love for her next clash against Bouchard to also be scheduled on Rod Laver Arena.

“It’s going to be a tough one,” said Dellacqua.

“(Bouchard) is a great player, she’s had really good results of late.

“She’s seeded here, she’s on the rise, she’s playing some really great tennis but so am I.

“It should be a great match.

“Hopefully we get the opportunity to play out here again in front of Australia and I’m looking forward to it.”