The Rod Laver Arena roof has been closed for Sunday night’s Australian Open final between Roger Federer and Marin Cilic because of the Melbourne heat.

Tournament directors have enacted the extreme heat policy prior to the 7:30pm final, with the temperature above 37 degrees within a half-hour of the first serve.

Previously in the tournament, the policy has only kicked in when the mercury hits 40 degrees with an additional wet bulb temperature threshold, relating to humidity levels.

Novak Djokovic and Gael Mofils struggled through a four-set second round match in 39 degree heat on centre court with a retracted roof.

That debacle led for calls from players and commentators for more protection for participants.

Closing the roof may benefit Federer, given he is seven years Cilic’s senior.

In any case, a titanic task awaits Cilic in the decider as he aims to become the first player to vanquish both Federer and Rafael Nadal on the way to the title at Melbourne Park.

Federer is an odds-on favourite to claim a remarkable 20th grand slam crown.

A victory for Federer in his 30th final at a major would continue an astonishing renaissance in which he and Nadal have reasserted their dominance over the men’s field.

Between them, the pair won all four grand slam titles last year and have racked up 35 over the course of their incredible careers.

Cilic will join an exclusive club if he is able to cause the upset and defeat Federer, having prevailed over Nadal in the quarter-finals when a leg injury forced the Spaniard to retire hurt early in the fifth set.

Just two players have beaten both modern-day giants on the way to a grand slam trophy.

Argentinian powerhouse Juan Martin del Potro achieved the feat at the 2009 US Open when he crushed Nadal in the semi-finals and edged past Federer to win his first major.

The reverse was the case at Flushing Meadows two years later when Novak Djokovic claimed a thrilling semi-final comeback win over Federer before seeing off Nadal in the title decider.