Rafael Nadal's ageing legs outlasted German teenager Alexander Zverev in an epic five-set match while Serena Williams sailed into the last 16 at the Australian Open on Saturday.
Nadal needed all his trademark grit against Zverev, 19, dubbed "the future of tennis", and his superior fitness showed as he eked out a thrilling 4-6, 6-3, 6-7 (5/7), 6-3, 6-2 win.
Germany's Zverev looked in discomfort as he won a punishing 37-shot rally nearly four hours into their contest as Nadal, still full of running, pressed his advantage in the final set.
It means Nadal, 30, follows fellow veteran Roger Federer into the last 16 of a contest now missing defending champion Novak Djokovic after his stunning defeat to Denis Istomin.
Williams, by contrast, had no such trouble as she brushed off fellow American Nicole Gibbs 6-1, 6-3 to maintain her charge towards a 23rd Grand Slam title. Williams, back after an injury break at the end of 2016, has been in brilliant form and she will take some stopping as she zeroes in on Steffi Graf's Open-era record.
The next player to take on Williams will be Barbora Strycova, who ousted France's Caroline Garcia to earn a shot at the world number two.
Elsewhere 117th-ranked Istomin built on his win over Djokovic by beating Pablo Carreno Busta 6-4, 4-6, 6-4, 4-6, 6-2 to reach the last 16 for the first time.
David Goffin halted towering Croatian Ivo Karlovic, who won a tournament-record 84-game match in the first round, to set up a clash against Austrian eighth seed Dominic Thiem.
Roberto Bautista Agut ousted fellow Spaniard David Ferrer 7-5, 6-7 (6/8), 7-6 (7/3), 6-4 and will next play third seed Milos Raonic, who beat Gilles Simon 6-2, 7-6 (7/5), 3-6, 6-3.
In the women's draw, Britain's Johanna Konta maintained her sizzling form with a dominant 6-3, 6-1 victory over former world number one Caroline Wozniacki. Konta's prize is a round-of-16 rematch with Russia's Ekaterina Makarova, whom she edged at the same stage last year, going 8-6 in the final set. Makarova, seeded 30, beat sixth seed Dominika Cibulkova in a three set marathon.
Mirjana Lucic-Baroni, who hadn't won an Australian Open match since 1998 before this year, extended her fairytale run by beating Greece's Maria Sakkari 3-6, 6-2, 6-3.
Next up for the 34-year-old Croatian, who put her career on hold to flee her abusive father, is American qualifier Jennifer Brady, who upset 14th seed Elena Vesnina.
Mirza, Bopanna enter mixed doubles second round
Sania Mirza and Rohana Bopanna advanced to the mixed doubles second round with respective partners at the Australian Open here
on Saturday. Bopanna and his Canadian partner Gabriela Dabrowski had to dig deep to beat Michael Venus and Katarina Srebotnik 6-4, 6-7, 10-7 in a super tie-breaker. A little later, second seeded pairing of Mirza and Croatia's Ivan Dodig got the better of reigning US Open defending champions, Laura Siegemund and Mate Pavic, in another first round match. The final scoreline read 7-5, 6-4.