The 14-time Grand Slam champion, 11 years older than Zverev, dug deep into his physical reserves to triumph 4-6, 6-3, 6-7 (5/7), 6-3, 6-2 in four hours and six minutes on Rod Laver Arena.

The Spaniard was staring at defeat after losing the third set in a tiebreaker but showed his trademark fighting qualities to deny the talented 19-year-old.

It was Nadal’s 18th win in 26 five-set matches and set him up for a crack at either French sixth seed Gael Monfils or German 32nd seed Philipp Kohlschreiber in the round of 16.

“I think everybody knows how good Alexander now is, as I say, he is the future of our sport and the present as well. A very tough match for me,” Nadal said.

“I needed to fight for every point, forget about the (tiebreaker) result and that’s what I tried.”

The win put Nadal into his 10th round of 16 at Melbourne Park in his 12th appearance.

Zverev was again desperately unlucky not to get his first win in his second meeting with Nadal.

Nadal saved a match point in overcoming him in the fourth round at Indian Wells last year, winning 15 of the final 16 points.

It was again another gripping evenly-matched clash between the pair with Zverev showcasing his enormous potential.

The German was bidding to join his elder sibling Mischa in the last 16 and make them only the third pair of brothers to reach the fourth round at a Grand Slam in the Open Era.

Titanic game 

Zverev struck early, breaking Nadal’s opening serve with a delightful backhand winner.

The Spanish great fought off a break point in his next service game and saved a set point at 5-4 before Zverev took the opening set on his third set point in the next game.

Nadal, bidding to win his second Australian Open after beating Roger Federer in the 2009 final, got more into the contest in the second set, breaking in the fourth game and levelling the match on his second set point in 38 minutes.

Zverev won a gripping third-set tiebreaker 7-5 to take the edge and forced Nadal to go the full distance to stay in the tournament.

The ninth seed hit straight back, breaking Zverev’s opening serve in the fourth set and carried the break through to send the match into a fifth set, where Nadal broke Zverev’s opening serve but gave it back in the fourth on his third break point.

A fantastic 37-shot rally ended with a Nadal netted backhand but the Spaniard would not relent and went on to break Zverev again in a titanic fifth game of the deciding set to take the advantage.

Zverev was cramping and the driven Nadal kept on the offensive, breaking the German’s serve a third time to lead 5-2 and serve out for the match.

(All images sourced from Reuters)