Rafael Nadal beats starlet Alexander Zverev in five-set thriller

The ninth-seeded Spaniard has shown signs of getting his form back in Melbourne, but he needed to be on top of his game against the breakthrough sensation of the men’s game.

Zverev, still just 19 years old, has already set his stall out as a future Grand Slam winner with some terrific victories over the last year. But his display against Nadal only underlined the German’s enormous potential.

The Spaniard, champion here in 2009, needed to be at his resilient best to come out on top after more than four hours of top quality shot-making and thrilling rallies which earned both players a huge ovation from the Rod Laver Arena crowd.

Zverev was just unable to stay with Nadal in a gripping deciding set, which the 30-year-old sealed when the 24th seed netted a forehand.

Returning to Melbourne Park as ninth seed after curtailing his 2016 season because of injury, Nadal will next face Gael Monfils of France as he bids for a 15th Grand Slam title.

"I won by fighting and running a lot," said Nadal. "I think everybody knows how good Alexander is. He's the future of our sport and the present too.

"It's been a very tough match for me. I didn't start playing my best and I was not feeling very well because I was losing too much court. When I felt I was feeling better I had more time to control from the baseline.

"It was a close one but he deserved to play a little more aggressive than me. I had to fight for every point."

While Zverev's performance reinforced his position in the vanguard of generation next, Nadal confirmed that he is healthy enough to take advantage of the early exit of 2016 champion Novak Djokovic from his half of the draw.

It was the younger man, however, who got off to the quicker start, grabbing a break in the opening game with a sumptuous backhand dropshot and moving the former world number one around the court.

Zverev had a 20 kph advantage over Nadal on first serve but the German was unable to dominate in the second set the way he did in the first and a single break evened up the contest.

The third set developed into a ding-dong battle with neither player able to snare a single break point and it was Zverev who edged the tiebreak with an angled winner, again off his backhand.

Nadal grabbed the only break of the fourth set on Zverev's first service game and tied the contest up with his eighth ace, sending it into a decider.

Another early break for Nadal appeared to set him on the path to victory but Zverev was having none of it and broke back, only fading when he started cramping after a series of marathon rallies to allow the Spaniard to claim the victory.

"I'm disappointed but I know that this was a great match, That was a great fight. There's a lot of positives in this match," Zverev said.

"I think he's probably one of the fittest tennis players in the history of the game. Obviously I wanted to win. I could have won. It's disappointing."