'Never seen that': Players beg ump to make wrong call

Gael Monfils and Novak Djokovic were so exhausted they were happy to go along with what was clearly a bad call.

So oppressive were the conditions at Melbourne Park on Thursday that the exhausted rivals actually appeared to beg the chair umpire not to overrule a clearly wrong call during the second set.

As the temperature hit 39.9 degrees on Thursday afternoon, the 'on-court temperature' at Rod Laver Arena peaked at 69 degrees.

Monfils felt the full effects of the scorching heat and succumbed after winning the first set.

At one stage in the second set, Monfils and Djokovic were so eager to get off court for a break, they were happy for a Djokovic fault to be called an ace.

Both players walked almost all the way to their chairs despite the chair umpire calling the ball out, with Monfils even challenging despite knowing full-well it was out.

Djokovic looked far from his best but was still too good for the enigmatic world No.39, maintaining his perfect record against Monfils with a 4-6 6-3 6-1 6-3 victory.

The Serbian 14th seed needed four match points, screaming in frustration on the third after Monfils hit a cross-court forehand winner to extend the two hours, 45-minute match.

A visibly drained Monfils was gasping for air between points and approached the chair umpire midway through the second set to warn that he was on the verge of collapsing.

"Monfils is physically in a daze right now," four-time grand slam winner Jim Courier said on the Seven Network.

"He is hurting badly. A 24-shot rally may have wounded him ... he has got nothing."

Monfils was seen by the tournament doctor and briefly left the court after giving up the second set.

with AAP