Australian Open: Extreme temperatures causes suspension of play at Melbourne Park

With the temperature into the mid-30s, the tournament's heat stress scale, which also takes into account humidity and wind speed, hit five just after 2pm, meaning play was stopped on the outside courts.

Among those affected was British number two Dan Evans, who had just taken a two-sets-to-one lead over Argentina's Facundo Bagnis in the first round.

Play continued under the roofs on the Rod Laver, Margaret Court and John Cain arenas.

The decision came just before the start of Andy Murray's clash with Matteo Berrettini on Laver, enabling it to start indoors.

It took until 5pm for conditions to improve sufficiently for play to resume on the outdoor courts.

Tuesday was forecast to be the hottest day of the tournament, with the possibility of thunderstorms and cooler temperatures from Wednesday.

Meanwhile, Russian flags have been banned at the Australian Open after one was displayed at a match between Russian and Ukrainian players.

The display drew a sharp rebuke for organisers from the Ukrainian ambassador to Australia, and Tennis Australia has now announced that Russian and Belarusian flags will not be allowed at Melbourne Park for the rest of the tournament.

Players from those two countries are playing under a neutral flag at the tournament amid the ongoing war in Ukraine.

Somewhat bizarrely, organisers initially decided spectators could bring the two nations' flags in, but displaying one has been deemed causing "disruption".

A statement read: "Flags from Russia and Belarus are banned onsite at the Australian Open.

"Our initial policy was that fans could bring them in but could not use them to cause disruption. Yesterday we had an incident where a flag was placed courtside.

"The ban will be effective immediately. We will continue to work with the players and our fans to ensure that this is the best possible environment to enjoy the tennis."

The flag was on show at Monday's first-round match between Russian Kamilla Rakhimova and Kateryna Baindl of Ukraine.

Ukrainian ambassador Vasyl Myroshnychenko reacted furiously, writing on Twitter: "I strongly condemn the public display of the Russian flag during the game of the Ukrainian tennis player Kateryna Baindl at the Australian Open today. I call on Tennis Australia to immediately enforce its 'neutral flag' policy."