MELBOURNE, Australia -- Rafael Nadal struggled for nearly four hours on Sunday to grind out a 6-3, 6-7 (4-7), 6-3, 6-3 defeat of Argentine Diego Schwartzman and reach the Australian Open quarterfinals for the 10th time.
2009 winner Nadal, who has also lost three other finals at Melbourne Park, played the longest match of the tournament so far as he beat Schwartzman, one of the smallest on the tour.
Third seed Grigor Dimitrov meanwhile withstood 36 aces from Nick Kyrgios in a match which featured nearly 140 combined winners, with the Bulgarian pulling out a 7-6 (7-3), 7-6 (7-4), 4-6, 7-6 (7-4) victory.
Dimitrov, who lost to the Australian this month in the Brisbane semis, was broken as he served for the match leading 5-4 in the fourth set, with the encounter leading to a tiebreaker.
In the decider, the seed finally took command as an easy volley winner yielded three match points, with Dimitrov converting on his second, an untouchable volley.
"What can I say, playing Nick is tricky," Dimitrov said, "It was one of those matches where you have to be locked in and take any opportunities you have. Even when I was serving for the match, I didn't feel it was over, I'm just glad to get through it."
Dimitrov will be bidding for his second straight Melbourne semifinal when he plays Kyle Edmund, the new British tournament hope in the injury absence of Andy Murray.
Edmund exceeded expectations with his first quarterfinal berth at the majors, 6-7 (4-7), 7-5, 6-2, 6-3 over Italy's Andreas Seppi.
The Brit came from a set and a break down, winning with 25 aces as part of 63 winners.
Nadal, with 16 Grand Slam honors to his name, lost his first set of the week to the South American, aa Schwartzman saved two match points before going down to the Spaniard who will hold onto his number one ATP ranking by the end of the event on January 28.