Melbourne, Australia, 22 January 2020 | AAP

Normal service has resumed with Ash Barty sweeping into the Australian Open third round in straight sets.

A three-set comeback winner in the opening round, top-seeded Barty needed barely an hour to see off big-hitting world No.48 Polona Hercog 6-1 6-4 on Wednesday.

Unlike Monday night when she dropped the first set against Lesia Tsurenko, a switched-on Barty dominated the opener in windy conditions at Rod Laver Arena, twice breaking Hercog’s serve.

The Slovenian put up more of a fight in the second, forcing Barty to hold from double-break-point down in the eighth game .

The world No.1 then gained a decisive third service break the very next game before closing out the contest, again from 15-40, in 66 minutes with four straight clutch first serves.

“It’s been another clean match today and very happy to get out of that one,” Barty said finishing with five aces, 16 winners, 16 unforced errors and saving all six break points she faced.

“It was different, end to end. The wind played a factor, particularly with the new balls.

“Polona has the ability to play off the court. It was about making as many balls as I could and, once I got my opportunity, I could take it.”

"This is the highlight of my day."

BFFs and former dubs partners @caseydellacqua and @ashbarty meet again 😍#AO2020 | #AusOpen pic.twitter.com/gF5Pp5sThA

— #AusOpen (@AustralianOpen) January 22, 2020

Barty next plays in-form Kazakh Elena Rybakina on Friday for a place in the last 16 after the Hobart International winner ended the run of Belgian qualifier Greet Minnen 6-3 6-4.

Should she win, Barty will play either her Open doubles partner Julia Goerges or American world No.19 Alison Riske in the fourth round.

Goerges upset 13th seed Petra Martic 4-6 6-3 7-5 earlier on Wednesday, while Riske – who ended Barty’s 15-match European winning streak last year at Wimbledon – hammered Zhu Lin 6-3 6-1.