Laura Robson stuns Petra Kvitova in Melbourne thriller

British number two Robson got off to a woeful start, losing a one-sided first set, before roaring back to take the second.

The 18-year-old eventually advanced after winning an epic third set, prevailing 2-6 6-3 11-9 in exactly three hours.

“I thought it was pretty ugly, but in terms of how tough it was to close it out at the end it was right up there with my best wins,” said Robson, who will face Sloane Stephens of the United States next.

“I never gave up, even when she went up a break twice in the third. I thought I had to get as many returns in as I can and in the end I thought I have nothing to lose so I relaxed on my serve and decided to go for it.”

Earlier in the day Andy Murray cruised to victory over Portugal’s Joao Sousa, winning 6-2 6-2 6-4 to reach the last 32.

Murray was relieved to have conserved energy as he raced to a straight forward win, dodging the worse of the day’s sweltering 40º heat in he process.

Murray swept aside his opponent in only an hour and 41 minutes as he booked his place in the third round against Lithuanian Ricardas Berankis, who defeated 25th seed Florian Mayer.

The Scot admitted afterwards that he had formulated a gameplan that could bring about a swift finish.

He said: “I got up a couple of breaks pretty quickly in the first two sets so I could play, not lose points, but I could try to shorten the points, which helps.

“I also served well today. I got a lot of free points on my serve. There were very few long rallies so it worked out well for me because it was really tough conditions.”

On the brutally hot conditions, he added: “It was actually OK when the sun was in but when it came out it got really hot, really quickly.

“It was a good match to get done in straight sets.”

Elsewhere there were comfortable second-round wins for defending women’s singles champion Victoria Azarenka and five-time winner Serena Williams. In the men’s, Swiss legend Roger Federer also progressed with ease.

Azarenka was ruthless in dispatching Eleni Daniilidou of Greece 6-1 6-0. “It was pretty hot,” admitted Azarenka, who will now play Jamie Hampton of the US or Thai qualifier Luksika Kumkhum. “That’s why I was trying to play fast.”

Williams took just one more game to beat Garbine Muguruza of Spain 6-2 6-0.

Men’s second seed Federer was in imperious form as he swept past Russia’s Nikolay Davydenko 6-3 6-4 6-4 in just 119 minutes.

Federer will now face Australian Bernard Tomic, who beat Daniel Brands 6-7 7-5 7-6 7-6.