Two former World No.1 players moved into the Grampians Trophy quarterfinals on Friday, but they took very different routes to the elite eight.

In her first match of the season, Victoria Azarenka of Belarus had to survive a closely-contested battle, as the No.3 seed came back from deficits in the opening set and the match-tiebreak, saving two match points to overcome Yulia Putintseva of Kazakhstan, 6-4, 1-6, [11-9].

Her fellow former top-ranked player, Angelique Kerber of Germany, had an easier time, as the No.8 seed eased past Ons Jabeur of Tunisia, 6-4, 6-4.

Two-time Australian Open champion Azarenka was behind 0-4 in the first set before reeling off six straight games to swipe the opener from Putintseva. The Kazakh turned the tilt around, charging through the second set and building a commanding 5-1 lead in the match tiebreak.

Azarenka made the tiebreak closer but Putintseva still reached double match point at 9-7. Azarenka saved both, the second with a superlative volley, leading to a change of ends at 9-9. All told, Azarenka grabbed the final four points of the match-tiebreak to eke out the victory after an hour and 43 minutes of play.

Azarenka will now face No.6 seed Anett Kontaveit in the quarterfinals, after the Estonian stopped Bethanie Mattek-Sands of the United States, 7-5, 7-5.

Angelique Kerber during her Grampians Trophy second-round match.

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Kerber, meanwhile, emerged triumphant after an hour and 19 minutes, in a battle between Top 30 players. Three-time Grand Slam champion Kerber picked up an early break in the first set which she never rescinded, then held on in the second set, completing the match with a love service hold.

"This is, for me, I think, a good sign that I can find my rhythm a little bit, and have another match tomorrow," Kerber said, after her win.

Kerber will now take on No.5 seed Maria Sakkari of Greece in the semifinals.

"I think it’s good to have another match against a good opponent," said Kerber. "It will be another good match where I can also get tested and play high-level tennis."

Sakkari earned a comprehensive win over Canadian teenager Leylah Fernandez, 6-2, 6-2.

"I was impressed with my performance, because I didn’t expect myself to play that well," said Sakkari, after her win. "I’m pleased with the way I played, and it’s great to get some matches before the [Australian] Open."

Azarenka vs. Kontaveit and Kerber vs. Sakkari are the quarterfinal matchups in the top half of the draw.

2021 Grampians Trophy Highlights: Sakkari sails past Fernandez into QF

In the bottom half of the draw, the highest-ranked player in the field was shocked, as Sorana Cirstea of Romania upset No.2 seed Belinda Bencic of Switzerland, 7-5, 6-2.

Cirstea converted five of her nine break points to oust Bencic, who was the highest-seeded player in the draw after the withdrawal of top seed Bianca Andreescu.

Cirstea will meet American Ann Li of the United States in the elite eight, after Li pulled off an upset of her own. Li, ranked 99th in the world, stunned World No.36 Veronika Kudermetova of Russia, 7-5, 6-3.

Kudermetova made the final of the season-opening event in Abu Dhabi but could not advance past 20-year-old Li in Melbourne.

No.7 seed Jennifer Brady of the United States and Barbora Krejcikova of the Czech Republic will face off in the other bottom-half quarterfinal. Brady beat Marta Kostyuk of Ukraine, 6-1, 6-4, while Krejcikova upset No.4 seed Elena Rybakina of Kazakhstan, 4-6, 6-2, [10-6].