Melbourne, Australia (SportsNetwork.com) - World No. 1 Rafael Nadal, three- time runner-up Andy Murray and four-time champion Roger Federer were among Thursday's winners, while fifth seed Juan Martin del Potro was a stunning second-round loser on another brutally hot day at the Australian Open.
On a day when the temperature soared to a sweltering 110 degrees and the show courts were covered by their retractable roofs, the 2009 champion Nadal put on a clinic in beating 17-year-old Aussie Thanasi Kokkinakis 6-2, 6-4, 6-2 at Rod Laver Arena.
"Very happy to see the roof out there today," Nadal said.
The reigning U.S. and French Open champion, who was a runner-up at Melbourne Park two years ago, will meet oft-injured, flashy former top-10 Frenchman Gael Monfils on Saturday. Nadal beat Monfils in a final at an Aussie Open tune-up in Doha just two weeks ago.
The stifling weather on Day 4 resulted in the tournament's 'Extreme Heat Policy' being put into effect, suspending action on the outside courts for a few hours. And there was also some rain, lightning and thunder on a wild- weather Thursday.
The biggest shock of the first four days occurred early Friday morning in Melbourne when capable Spaniard Roberto Bautista Agut toppled the former U.S. Open champion del Potro 4-6, 6-3, 5-7, 6-4, 7-5, with play wrapping up at 1:20 a.m. local time.
Bautista Agut set himself up with a match point via ace, moving the score to 40-15 in the 12th game of the final set, and sent del Potro packing when the big Argentine netted one final forehand return after 3 hours, 50 minutes.
The 6-foot-6 "Delpo" has never advanced beyond the quarterfinals in Melbourne and exited in the third round here last year.
Meanwhile, a fourth-seeded Murray got past game Frenchman Vincent Millot 6-2, 6-2, 7-5 at Laver, where the roof was re-opened after the weather improved.
Murray won the last 23 points of the match to come back from 1-5 down in the third set.
"It was 6-5 when I went to serve for it, and someone shouted out, 'You won 19 in a row'," Murray said. "I would say that's probably the most I'd ever won in my career by far. I don't really know how I did it."
The two-time major titlist and reigning Wimbledon champion lost to Novak Djokovic in last year's marquee Aussie finale. Murray's third-round opponent will be Spanish left-hander Feliciano Lopez.
The sixth-seeded former No. 1 Federer played under the roof at Hisense Arena and dismissed Slovenia's Blaz Kavcic 6-2, 6-1, 7-6 (7-4) for his 70th career win at the Aussie Open (70-8). The 17-time Grand Slam king is seeking his first Aussie title since 2010.
Federer said he didn't mind the switch to Hisense after he'd played 63 consecutive matches at Laver Arena since 2004.
"It was nice ... it's not really different to Rod Laver Arena really," Federer said. "Dimensions feel the same, the crowds were really nice, great atmosphere. I was happy playing there."
The 32-year-old Federer will return to the court against Russian Teymuraz Gabashvili on Saturday.
Tenth-seeded Frenchman Jo-Wilfried Tsonga, the 2008 runner-up to Djokovic, topped Brazilian qualifier Thomaz Bellucci 7-6 (8-6), 6-4, 6-4, while 11th- seeded Canadian slugger Milos Raonic downed Romanian veteran Victor Hanescu 7-6 (11-9), 6-4, 6-4. Tsonga will take on fellow Frenchman Gilles Simon, while Raonic will tangle with rising Bulgarian star Grigor Dimitrov in the round of 32.
Sixteenth-seeded Japanese Kei Nishikori reached the third round by besting Serb Dusan Lajovic 6-1, 6-1, 7-6 (7-3) prior to the suspension of play. Nishikori's next opponent will be American Donald Young, who upset 24th-seeded Italian Andreas Seppi 6-4, 2-6, 6-3, 4-6, 7-5.
In other action involving seeds, a No. 18 Simon outlasted Croat Marin Cilic 4-6, 7-6 (7-3), 6-7 (5-7), 6-1, 6-2; the No. 22 Dimitrov defeated Taiwan's Yen-Hsun Lu 6-3, 6-3, 7-6 (13-11); a No. 25 Monfils sacked American Jack Sock 7-6 (7-2), 7-5, 6-2; a No. 26 Lopez erased German Michael Berrer 6-4, 7-6 (8-6), 6-4; No. 27 Frenchman Benoit Paire fought back to stop promising 18- year-old Nick Kyrgios, 6-7 (5-7), 6-7 (5-7), 6-4, 6-2, 6-2 in the final result of the day; and Gabashvili took out No. 31 Spaniard Fernando Verdasco 7-6 (7-1), 3-6, 2-6, 6-4, 6-4. Paire-Kyrgios ended at 1:40 a.m. after 3 hours, 20 minutes. Paire's third-round opponent will be the sweet-swinging Bautista Agut.
Two other results saw France's Stephane Robert get past Pole Michal Przysiezny 7-6 (7-3), 6-1, 6-7 (3-7), 6-1 and Slovak Martin Klizan beat Slovenian Blaz Rola 6-4, 6-3, 5-7, 7-6 (7-2). Robert and Klizan will square off on Day 6.
Also on Thursday, it was learned that eighth seed Stan Wawrinka received a walkover into the fourth round when 28th-seeded Canadian Vasek Pospisil pulled out of the draw.
The third round will get underway Friday, including a match for the second- seeded former world No. 1 Djokovic.
Seeking a fourth straight and fifth overall Aussie Open title, the Serbian superstar will battle Uzbekistan's Denis Istomin on Day 5.
In other action involving top-10 seeds,No. 3 David Ferrer will take on 29th- seeded fellow Frenchman Jeremy Chardy, No. 7 Tomas Berdych will face Bosnia's Damir Dzumhur and No. 9 Richard Gasquet will be opposed by 1th-seeded former top-10 star Tommy Robredo.