Spanish second seed Rafael Nadal's renowned endurance and fighting qualities shone out as he reached his first Australian Open quarter-final with a comeback five-set win over Scottish teenager Andy Murray in Melbourne.

Nadal came back from two sets to one down, winning 10 of the last 11 games to triumph 6-7(3-7) 6-4 4-6 6-3 6-1 in what was the first meeting of two of the brightest young stars of the sport.

The 20-year-old will play Chile's Fernando Gonzalez in the quarter-finals, after Gonzalez upset fifth-seeded American James Blake 7-5 6-4 7-6(7-4) on Monday.

Nadal, who missed the Australian Open through injury last year, has now reached at least the quarter-finals of every grand slam event since winning the French Open, making the Wimbledon final and exiting at the quarter-final stage in the US Open.

The variety and finesse of 19-year-old Murray's all-court game provided a fascinating counter to his powerful baseline pounding, in what surely heralds a long-lasting rivalry.

Throughout the early stages Murray was able to throw Nadal's reliable backcourt game off-kilter by regularly advancing to the net, where he showed delightful touch, and by mixing some ferocious ground strokes with frequent drop shots.

In a high-class match full of momentum swings, Murray took the opening set in dramatic style, winning a tiebreak with the help of two video replay-assisted corrections.

The first came at 3-3 when a Murray serve down the centre was called wide.

The Scotsman challenged the call, the replay showed the ball clipped the line and Murray was awarded an ace and a 4-3 lead.

Nadal gave up the next two points cheaply on his own serve to hand Murray three set points, with the teenager seizing the first, again with some video assistance.

A Nadal groundstroke was initially called long, before the linesman changed his decision, but the replay that resulted from Murray's challenge showed he was right the first time and the 19-year-old took the set.

The momentum was running all Murray's way early in the second set and he was quickly up 4-1 with a break.

But the match took its first major twist, as Nadal strung together the next five games, helped by a seeming physical ailment to Murray, who continually clutched at his right side during the final two games of the set.

While he did not call for medical assistance, the problem seemed to affect his concentration as he meekly gave up his serve in the ninth game of the set and allowed Nadal to serve it out in the following game with little resistance.

Murray's decline continued into the third set, as he gave up his serve with a double-fault in the third game and Nadal held his serve in the next game for a 3-1 lead.

But that only ushered in another momentum swing as Murray suddenly regained his spark to win five of the next six games and take the set.

The Scotsman played some delightful tennis during that patch, notably a perfect drop volley in the seventh game and some ripping baseline shots in the final game to break Nadal's serve.

But It was Nadal who had the final say, assuming control late in the fourth set to win the final four games level the match, then never letting up in the decider.

While Murray fought hard in the early games of the final set, the physical and mental strength that have helped Nadal win his last five five-set matches allowed him to work his way on top, with the match finishing just nine minutes short of the four-hour mark at 1.50am (AEST).

Nadal paid credit to Murray and said it was an important victory for him.

"It was very, very tough and he's a great player, he's playing at an unbelievable level," Nadal said.

"It was a very important match for me, I need one match like this against one big player so I'm very happy."

He said his fitness served him well, but the final set was not as straightforward as the scoreline suggested.

"I felt good physically in the fifth set, so that's important in these moments," Nadal said.

"He had a lot of chances in the fifth set in the beginning.

"I was trying all the time my best, trying to fight every point and just like that I can win this match."

Murray expressed pride in his performance and said his standard of play was probably higher than when he beat world No.1 Roger Federer in a Masters Series tournament in Cincinnati last year.

He said he hoped the match would generate a healthy rivalry with Nadal.

"I'm not as good a player as him and haven't achieved anything like he has, but with matches like that I think the next time we go on court everybody will be looking forward to watching it," he said.

Murray also said he had told Nadal afterwards he wanted him to win the tournament.

"I hope he does because everyone wants someone to come along and rival Federer and he could be the one to do it," he said.

Brought to you by AAP © 2024 AAP