Ajla Tomljanovic, newly installed as Australia’s No.1 women’s player, has made another significant breakthrough at the WTA’s Istanbul Cup.

The 28-year-old, who’s taken over the domestic top spot now that Ash Barty has hung up her racquet, reached the quarter-finals of the Turkish event on Thursday with victory over Ukrainian Lesia Tsurenko.

Tomljanovic took a hard-fought first set 6-4 before the luckless Tsurenko had to retire at 1-0, 30-0 down in the second with a shoulder injury.

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The victory meant Tomljanovic has progressed to her first quarter-final in any event since her career-best grand slam performance at Wimbledon last year, where she also reached the last-eight before being beaten by Barty.

It was only the second quarter-final that the hard-working world No.41 Tomljanovic has reached in her last 52 events, stretching back over two-and-a-half years.

It also gives her a boost going into the business end of the clay court season, with the prospect that she’ll move to a career-high ranking in the mid-thirties should she beat her next opponent, Kazakhstan’s Yulia Putintseva in Friday’s last-eight clash.

That, though, will be a tough ask as world No.51 Putintseva looked in dominant form in her 6-2 6-0 win over Sweden’s Rebecca Peterson.

The Florida-based Tomljanovic has had mixed results since her Wimbledon run, with Thursday’s win being the first time she’s managed back-to-back wins since qualifying for the Dubai Championships in February.

After a slow start in the face of real aggression from 2015 Istanbul winner Tsurenko, who broke immediately, Tomljanovic began to find her rhythm to break back, hitting with more authority in the eighth game.

But after then powering ahead for the first time at 5-4, Tsurenko needed the trainer and a medical timeout as she was treated for a problem with her serving shoulder.

On resumption, it was clear the world No.135 was struggling with her delivery as Tomljanovic grabbed the break and the set after 49 minutes.

And after Tsurenko lost her first two points on serve in the second set, giving up on a drop shot chase, she went straight to the net to offer her hand to the sympathetic Tomljanovic.

It was another dispiriting moment for the 32-year-old Ukrainian veteran Tsurenko, who’s been in torment since the invasion of her homeland by Russian troops.

She posted an appeal for help on social media after revealing how she had “nowhere to go” when the conflict spread to her home city of Kyiv and was subsequently overwhelmed by the offers of help.

Tsurenko says she’s been suffering from a “constant headache” and panic attacks after watching TV pictures of the dreadful scenes back home.