TOKYO, Japan - Wildcard Victoria Azarenka has reached her third quarterfinal of the season at the Toray Pan Pacific Open, defeating No.8 seed Ashleigh Barty 6-4, 6-2 in one hour and 17 minutes.

"I think I played a lot better than in the first round," said the 29-year-old - who had spent one hour and 52 minutes on court on Tuesday to beat Kurumi Nara 6-4, 7-5. "I felt I really controlled today and found the court really well, and I returned better than in the first round."

The win is the former World No.1's fifth Top 20 victory of her comeback from maternity leave, and first since beating Madison Keys, Anastasija Sevastova and Karolina Pliskova to reach the Miami semifinals in March. Since then, Azarenka had lost five consecutive matches against Top 20 players. Meanwhile, it also breaks Barty's streak of five tournaments in which she has won multiple matches stretching back to Wimbledon.

There were a number of unknown quantities heading into the match that made it particularly intriguing for fans - not least in seeing how, in the two players' first meeting, their games would match up. The same seemed to be true on court: momentum tilted first slightly one way and then the other over the course of several tightly contested games in which the pair probed each other's strokes to feel out their best potential tactics.

For the Australian, there was initial success with some nifty hooked forehand angles and judicious ventures to the net. But she increasingly found herself on the run as Azarenka pumped relentless, heavy groundstrokes from side to side. Although Barty demonstrated defensive skills of the highest calibre at times, particularly on the lob, Azarenka was largely immune to getting entangled in the 22-year-old's biting slice - and a willingness to come forward herself would also pay dividends. A desperate stab volley and a huge off backhand return paved the way to the first break for the Belarusian to go up 3-2.

That would be the first of three consecutive breaks of serve as both players mixed loose errors into their play - but at 4-3 up, Azarenka staved off a fourth, with Barty's forehand going awry on break point and the two-time Australian Open champion holding with a neat backhand volley. Two games later, the Nottingham champion had a half-chance to claw her way back into the set after saving two set points - but facing a third, she sent an inside-out forehand into the net to lose the opening stanza.

Seemingly rattled, Barty's level dipped immediately at the start of the second set as the Sydney finalist offered up two double faults off the bat. Azarenka needed no encouragement to seize the lead with a forehand winner.

As the US Open doubles champion's first serve percentage dropped to 47%, her unforced error tally rose to 22 - and four games later, another Barty double fault was followed by a forehand over the baseline to sink to a double break deficit.

Two cheap errors from Azarenka opened the window slightly for a potential comeback, and aggressive returning from Barty clawed one of the breaks back. But even the Montréal semifinalist's normally reliable backhand slice was misfiring now, and she continued to be plagued by double faults with a fifth putting her down 2-5.

The World No.63, who struck 13 winners and would land an impressive 70% of her first serves, resumed control, serving out a drama-free final game to 15 to set up a quarterfinal tilt against either No.1 seed Caroline Wozniacki or Camila Giorgi.