The four-time major winner was serving at 5-4 in the third set, 2 hours and 38 minutes into her second-round match against No. 44-ranked Karin Knapp on Thursday. But the reprieve wouldn't apply to the pair on Rod Laver Arena, because the long-delayed Extreme Heat Policy only kicks in at the end of sets in progress. It took another 50 minutes before Sharapova converted her fourth match point for a grueling 6-3, 4-6, 10-8 win.
The temperature was 39 C (102 F) when Sharapova's match started at just after 11 a.m. local time and increased to almost 43 C (109 F) by the time she finished during the third straight day of a heat wave in sweltering Melbourne. At 3 hours and 28 minutes, it was the longest women's match so far in the tournament.
"I wanted this match," Sharapova said. "I didn't play my best tennis; I didn't do many things well ... (but) I got through it, and sometimes that's what's important.
"When you win match point you get off the court, no matter how you feel and how tough it was ... I love these moments."
Caroline Wozniacki followed Sharapova on Rod Laver Arena and, with the roof closed, described the conditions as "pleasant" in her 6-0, 1-6, 6-2 win over Christina McHale. Roger Federer played on the second show court at Melbourne Park for the first time in a decade, and raced to a 6-2, 6-1, 7-6 ( 4) win over Blaz Kavcic under the roof at Hisense Arena.
He was playing simultaneously with Rafael Nadal for the first time in years at Melbourne Park. Nadal had no trouble in a 6-2, 6-4, 6-2 win over Australian wild-card entry Thanasi Kokkinakis under the roof on Rod Laver Arena.
The problems with weather didn't end after the temperatures subsided slightly — night play was suspended on more than a dozen courts because of lightning.
Earlier, at the height of the heat, Sharapova wasted three match points on serve in the 10th game of the third set, and then had to save break points and serve to stay in the match. She earned a crucial break seven games later, but it wasn't a simple matter of serving out.
Three double-faults in the last game — Sharapova's 10th, 11th and 12th of the match — gave Knapp another break point and a chance to extend it further. But with a reflex backhand from Sharapova that just caught the line, and two errors from Knapp, it was over.
She hit 34 winners but made 67 unforced errors in an increasingly frustrated push to finish points early.
The four-time major winner will next meet No. 25 Alize Cornet of France, who sobbed on court after beating Camila Giorgi of Italy 6-3, 4-6, 6-4 in 2 1/2 hours.
"I went really further than my limits. It was really hot, that's why I'm so emotional," Cornet said of the conditions.
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.
No. 11 Simona Halep had a 4-6, 6-0, 6-1 win over American Varvara Lepchenko, who only won one game after needing treatment for heat-related problems late in the second set.
In other results, No. 16 Carla Suarez Navarro beat Galina Voskoboeva 7-6 (2), 3-6, 8-6, No. 20 Dominika Cibulkova beat Switzerland's Stefanie Vogele 6-0, 6-1 and Kazakhstan qualifier Zarina Diyas beat New Zealand's Marina Erakovic 6-4, 6-0.
In the only men's match completed before the Extreme Heat Policy was invoked, No. 16 Kei Nishikori had a 6-1, 6-1, 7-6 (3) win over Dusan Lajovic. Jo-Wilfried Tsonga started his match under the blazing sun and finished it with a roof over the court in beating Thomaz Bellucci 7-6 (6), 6-4, 6-4 at Hisense Arena.