Rafael Nadal swept into the Australian Open third round under the Rod Laver Arena roof on Thursday but Juan Martin Del Potro was sent packing as sweltering temperatures, lightning and rain caused chaos on the outside courts.
Fifth seed Del Potro, whose match was shunted back to the late evening by the disruptions, was the first major casualty of the men's draw in the early hours of Friday morning when he lost 4-6 6-3 5-7 6-4 7-5 to 62nd ranked Spaniard Roberto Bautista.
On a third consecutive day of sauna-like heat and with temperatures climbing towards a peak of 43.4 degrees Celsius (110 Fahrenheit), organisers finally enacted the third stage of their "Extreme Heat Policy" after three hour's play.
Play was suspended for more than four hours on the exposed outer courts and, in a bizarre turn of events, the players had been back on court for less than two hours when a thunderstorm sent them scuttling back to the locker rooms.
Matches continued on the Rod Laver Arena and Hisense Arena throughout both stoppages, the latter lasting nearly two hours, after the retractable roofs over the showcourts were closed.
That allowed Nadal, Victoria Azarenka and Roger Federer to charge through their second round ties before the Rod Laver Arena was again exposed to the elements for Andy Murray to join them in the third round in the evening cool.
"For me, everything was fine," defending champion Azarenka said after beating Barbora Zahlavova Strycova 6-1 6-4.
"Played under the closed roof so lightning couldn't hit me. I didn't feel the heat. I didn't get sunburned. I was in the perfect conditions today."
Third seed Maria Sharapova had a tougher time, though, and a quirk of the rules meant her match against Karin Knapp was concluded in the full glare of the sun some 50 minutes after it was adjudged too dangerous to play.
The Russian reflected the confusion and anger of players over the last three days at a perceived lack of transparency over when the Extreme Heat Policy is put into force.
"No one really knows what the limit is," she said after closing out a 6-3 4-6