MELBOURNE, Australia - Barbora Krejcikova's Australian Open mixed doubles title defence remains alive after the No.5 seed, partnering Nikola Mektic, narrowly edged out Amanda Anisimova and Nick Kyrgios, 4-6, 6-4, [10-8] to reach this year's quarterfinals.

Krejcikova, who won her first mixed doubles major last year alongside Rajeev Ram, was the most reliable player on court, and the only one of the four not to face a break point on her serve - indeed, the 24-year-old would lead her team by serving first in both the second set and super-tiebreak.

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However, the Czech-Croat duo were forced to work hard by singles stars Anisimova and Kyrgios, who frequently treated the crowd to dazzling shotmaking and were ultimately only just held off from surging to a comeback in the tiebreak.

The American-Australian pair had already shown their ability to overturn deficits in the first set. From 1-3 down, with Anisimova having conceded her first service game, they roared through six of the next seven games, going after the Mektic serve with relentless aggression. A particularly phenomenal passage of play saw both Anisimova and Kyrgios strike clean return winners off the Croat's delivery in the final game of the first set, before Kyrgios turned around to seal a 55-second hold to open the second.

As the set drew on, though, with the Krejcikova serve remaining impregnable, the unseeded duo began to wobble, with Anisimova's volleying going awry in key moments and the 18-year-old dropping serve again in the seventh game after an emphatic Mektic cross.

Though Anisimova and Kyrgios would draw level by capturing the still-vulnerable Mektic serve for 4-4, a Kyrgios double fault - and ensuing racquet smash - would give Krejcikova and Mektic another opportunity to move ahead, taken when another Anisimova volley found the net.

Krejcikova and Mektic would start the super-tiebreak in sharper form, quickly building a 5-1 lead. This would prove to be just enough: facing four match points, Anisimova and Kyrgios began to mount a comeback, saving the first with one of the best all-court points of the day and two more with Kyrgios service bullets. But on the fourth, appropriately enough, Krejcikova shrugged off the missed chances to fire her own faithful delivery down the ‘T’ for a service winner, setting up a last-eight date with Nadiia Kichenok and Rohan Bopanna.

Latisha Chan, who had earlier reached the semifinals of the Women’s Doubles, continued her success on the doubles court as she partnered Ivan Dodig to a thrilling, 6-3, 4-6, [10-8] victory over Andreja Klepac and Edouard Roger-Vasselin.

The No.6 seeds withstood a great deal of pressure over the course of the match, saving 10 of 13 break point chances, before pinching a quarterfinal spot in the super-tiebreak.

Their opponents in the last eight will be No.3 seeds Gabriela Dabrowski and Henri Kontinen, who had a more straightforward outing against Australian wildcards Jessica Moore and Matthew Ebden.

Nevertheless, they were forced into a second-set tiebreak before emerging, 7-5, 7-6(5) victors in one hour and 24 minutes.

Completing the line-up in the quarterfinals will be Bethanie Mattek-Sands and Jamie Murray, who kept their strong run going with a 6-2, 7-5 win over Jelena Ostapenko and Leander Paes.