I am happy I don't have to go from night to day, then back to night.
"I would like to see more players just being really themselves in front of the press, being more relaxed about it, not worrying so much about making mistakes. Used to go to Dubai when it was 45 - 38 seems nearly OK".
Other top seeds did not handle the heat almost as well, especially 2014 Aussie champion and No. 9 seed Stan Wawrinka, who fell to American Tennys Sandgren - ranked No. 97 in the world - 6-2, 6-1, 6-4. "But sure it's helpful to play now (night) than during the day".
It was the Latvian who ended her Grand Slam comeback in the last 16 of the US Open in 2017 as she returned from a drug ban.
A Struff error opened the door for a two-set lead and Federer coolly walked through it with a trademark backhand. However his first game in Australian Open 2018, he lost to Damir Dzumhur in Sydney.
Sixth seed Karolina Pliskova and eighth seed Caroline Garcia also progressed, in contrast to the other side of the draw that saw Venus Williams, Sloane Stephens and Coco Vandeweghe crash out on Monday.
It was his earliest Grand Slam exit in seven years as he fights back from a wrist injury. Clearly, the 2014 champion was too ambitious. He was ranked second worldwide.
"I was thinking a lot about what happened at the tournament a year ago because it was my favourite tournament of the whole season.it was such a surprise", Federer said. "To be that far already, it's more than what we could have expected".
Sandgren - his first name comes down from his great-grandfather - said he held his celebrations in check out of respect for an injured opponent.
The heat peaked during Djokovic's win.
When both these boxes are ticked, matches on outside courts are halted and roofs closed on all three indoor-capable venues.
It will be the 19th meeting between the two players.
Djokovic said tournament organisers should consider waiting until temperatures dropped before sending players out on court.
"It was tough conditions, brutal, especially the first 90 minutes", he said.
Ashleigh Barty, backed by a roaring home support on Rod Laver Arena, rallied from a set down to beat Italian Camila Giorgi 5-7 6-4 6-1 in the second round.
While he didn't mention any kind of boycott the Swiss veteran said players must present a united front to force the increase.
"There are certain days where you just have to, as a tournament supervisor, recognize that you might need to give players few extra hours, " he said.
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