Novak Djokovic is aware of the threat Bernard Tomic poses after the Australian No.1 overcame London’s extreme heat and humidity to set up a Wimbledon blockbuster with the world No.1 and defending champion.

Tomic complained of dizziness as temperatures nudged 30 degrees but showed true grit to grind out a 7-6 (7-3) 6-4 7-6 (7-5) second-round win over talented young Frenchman Pierre-Hugues Herbert on Wednesday.

The 27th seed required medical assistance late in the third set but dug deep to book a showcourt meeting Djokovic on Friday.

Tomic was particularly impressive on serve, not broken once in his two-hour triumph, to leave Djokovic on guard ahead of their second tussle at the All England Club.

The Serb edged Tomic in a tight quarter-final four years ago before going on to lift the trophy for the first time and is expecting another stern test.

“This is the surface that he loves playing the most on. So it’s going to be a difficult match,” Djokovic said.

“I remember – was it 2011, I think, quarter-finals, we played against each other – four tough sets. So I’m not expecting anything easy there.”

Landing 72 per cent of first deliveries, Tomic barely dropped a point on serve in the opening set against Herbert.

He hung tough in the game immediately after seeking treatment at 5-4 in the second set to to hold from 15-40 and secure a two-sets-to-love lead.

The French qualifier needed 21 aces to stay in the fight, but Tomic’s class and experience shone through as the world No.27 recovered from 4-1 down in the third-set tiebreaker to live up to his seeding status.

“I was very dizzy out there,” Tomic said.

“I didn’t sleep well yesterday and the day before, probably getting three or four hours of sleep.

“I was fatigued and starting to get dizzy out there with the heat hitting me.

“It was tough, so I had to slow things down. I had to catch my breath.

“It was not that easy, that situation for me in the second. I was feeling bad.

“Hopefully I can get a good night’s sleep in tonight. I just haven’t been sleeping well here. It’s been too hot.”

Tomic knows he needs plenty of rest in order to challenge Djokovic, but gives himself a shot of springing a boilover.

“I will recover as much as I can from this match,” he said.

“Obviously he’s the No.1 player in the world. Against him, you have to go out with a different mindset and different belief.

“I have to serve very well to have any chance of winning.”