MELBOURNE, Australia — Melbourne Park was expected to be scorching on Friday, with temperatures reaching 42 Celsius (108 Fahrenheit) for the fifth day of the Australian Open.

While top-seeded Rafael Nadal, Nick Kyrgios and Caroline Wozniacki were among those scheduled to play their third-round matches, tournament officials were expected to keep a close eye on the rising temperatures. When play began at 11 a.m., it was already 35 C (95 F).

On Thursday, officials were criticized when play continued after the temperature reached 40 C (104 F), and several players, including Gael Monfils, complained it should have been stopped.

The tournament has an Extreme Heat Policy which goes into effect when the air temperature exceeds 40 Celsius and the wet-bulb reading, which takes into account other factors such as humidity, is more than 32.5 C (91 F).

When both those temperatures are exceeded, matches on outside courts are supposed to be suspended and the roofs closed on all three main stadiums — Rod Laver Arena, Margaret Court Arena and Hisense Arena.