MELBOURNE, Australia — Maria Sharapova toiled in 109-degree Fahrenheit temperatures for more than 3½ hours on Rod Laver Arena and could count herself among the unlucky early starters at the oppressively hot Australian Open on Thursday.
After organizers finally decided to suspend matches due to extreme temperatures in a heat wave gripping southeastern Australia, late lighting and rain caused further delays on day four.
Caroline Wozniacki highlighted the unpredictable Melbourne weather, describing the conditions as ‘‘pleasant’’ when she played on Rod Laver Arena immediately after Sharapova. And comparatively, it was. Rafael Nadal and Roger Federer also enjoyed the milder temperatures when they played evening matches indoors.
Organizers invoked their ‘Extreme Heat Policy’ and the roofs on the two main arenas were closed in the afternoon. Matches on outside courts, meanwhile, were suspended for more than four hours until temperatures dropped.
Problems with the weather didn’t end there — thunderstorms, lightning and rain showers hit during the early evening, forcing another suspension of play for matches on the outer courts.
Defending champion Victoria Azarenka was spared, playing indoors when she beat Barbora Zahlavova Strycova 6-1, 6-4.
Her main rival on the bottom half of the draw had to endure the harshest conditions of the day.
The temperature was 39 C (102 F) when Sharapova’s match against No. 44-ranked Karin Knapp started just after 11 a.m. local time. It increased to almost 43 C by the time she finished off a 6-3, 4-6, 10-8 win on her fourth match point, 50 minutes after her first. 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.’’
At the height of the heat, Sharapova, dripping in sweat, 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’ll 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.
Wozniacki had a 6-0, 1-6, 6-2 win over American Christina McHale and No. 13 Sloane Stephens, who beat Serena Williams here last year in the quarterfinals, beat Ajla Tomljanovic 3-6, 6-2, 7-5.
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.
Federer said he didn’t mind the switch — he’d played 63 consecutive matches on Rod Laver 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.’’
He was playing at the same time as 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.
‘‘Very happy to see the roof out there today,’’ Nadal said.
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. He 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 for nearly four hours due to the heat.
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.
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.
No. 22 Grigor Dimitrov beat Lu Yen-hsun 6-3, 6-3, 7-3 (11),