MELBOURNE, Australia -- Top-seeded Rafael Nadal advanced to the third round at the Australian Open with a 6-2, 6-4, 6-2 win over Australian wild-card entry Thanasi Kokkinakis on Thursday.

Nadal won the match in 1 hour, 53 minutes and was rarely troubled under the roof at Rod Laver Arena in a delayed schedule at Melbourne Park, where temperatures hit 109 Fahrenheit earlier Thursday and forced organizers to suspend matches on outer courts. All outside matches were suspended for more than four hours until temperatures dropped.

"Very happy to see the roof out there today," Nadal said.

Playing at the same time as Nadal for the first time in years at Melbourne Park, Roger Federer raced to a 6-2, 6-1, 7-6 (4) win over Blaz Kavcic under the roof at Hisense Arena.

It was Federer's first Australian Open match away from Rod Laver Arena in a decade. He had played 63 consecutive matches on Rod Laver since 2004, when he won the first of his four Australian Open titles, and he said he didn't mind the switch.

"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."

Fifth-seeded Juan Martin del Potro is out of the Australian Open, losing 4-6, 6-3, 5-7, 6-4, 7-5 to Spaniard Roberto Bautista Agut in a big second-round upset.

It was Bautista Agut's first win in seven matches against a top 10 player, and del Potro's fourth second-round exit in eight years at the season's first major.

The match lasted 3 hours and 53 minutes and ended at 1:20 a.m. Friday after a long day of suspensions and delays in matches due to extreme heat and storms.

Del Potro won his 18th career singles title last week by beating Bernard Tomic in the final of the Sydney International, a key warmup event for the Australian Open.

Three-time Australian Open finalist Andy Murray won the last 23 consecutive points to come from 5-1 down in the third set for a 6-2, 6-2, 7-5 second-round win over French qualifier Vincent Millot.

Murray, the reigning Wimbledon champion, has never lost an ATP-level match to a player ranked outside the top 200. Millot is ranked No. 267 and was playing in just his third Grand Slam event.

Murray was the finalist at Melbourne Park in 2010, 2011 and 2013, losing to Novak Djokovic twice and Federer once.

He is playing his first tournament since minor back surgery in September.

Jo-Wilfried Tsonga started his match under the blazing sun and finished it with a roof over the court while beating Thomaz Bellucci 7-6 (6), 6-4, 6-4.

The tournament's extreme heat policy was put into effect during the match when the temperature exceeded 108 degrees, meaning a brief delay while the roof at Hisense Arena was closed following the completion of the first set.

Earlier, Kei Nishikori advanced to the third round, starting and finishing quickly in a 6-1, 6-1, 7-6 (3) win over Dusan Lajovic of Serbia.

The 16th-seeded Nishikori, who won the warm-up exhibition tournament at Kooyong last week in Melbourne and then endured a five-set first-round win here, will next play American Donald Young, who beat No. 24 Andreas Seppi 6-4, 2-6, 6-3, 4-6, 7-5 in one of the matches suspended due to the heat.

Nishikori's match finished in temperatures of 106 Fahrenheit.

Crowd numbers have been down compared with previous years at Melbourne Park, and hardy fans have had to be resourceful to keep cool. The concourse level at Rod Laver Arena, where tickets are not needed for entry, was crammed with hundreds of fans trying to escape the outside temperatures.

Problems with the weather didn't end after the temperatures subsided -- thunderstorms, lightning and rain showers hit Melbourne Park during the early evening, forcing another suspension of play for matches on the outer courts.

Also in the men's draw, No. 25 Gael Monfils beat Amercian Jack Sock 7-6 (2), 7-5, 6-2 in an evening match.

Organizers announced later that Canadian Vasek Pospisil withdrew with a back injury from his scheduled third-round match Friday against No. 8 Stanislas Wawrinka.