MELBOURNE, Jan 24 (Reuters) - Jannik Sinner suffered cramp in extreme heat and lost his first set since October but the Australian Open defending champion battled through to the fourth round with a gutsy 4-6 6-3 6-4 6-4 win over American Eliot Spizzirri on Saturday.
In extraordinary scenes at Rod Laver Arena, the Italian limped over to his players' box in desperation midway through the match and was told by coach Darren Cahill to walk through the rest of the third set if necessary to get to a break.
With his serve broken a point later and trailing 3-1, Sinner was reprieved as the tournament's extreme heat policy was invoked to allow time for the stadium's roof to close.
It proved pivotal, as when play resumed Sinner broke Spizzirri twice to take the set and again in the seventh game of the final stanza on the way to one of the most dramatic victories of his young career.
Keen to get a head start on his recovery, Sinner cut short his on-court interview after discussing the challenges he had faced during the match.
"I struggled physically a bit today," the 24-year-old said. "I got lucky with the heat rule, I know they closed the roof.
"I took my time, as the time passed I felt better and better."
Sinner said cramp had started in his leg and then he felt it in his arms.
"So I was cramping a bit all over. This is the sport so I know this is an area I need to improve," he added.
"At the end of the day, tennis is a very mental game. I just ties to play as calm as possible."
Sinner will meet fellow Italian Luciano Darderi for a place in the quarter-finals as he continues his bid for a third consecutive title at Melbourne Park where he struggled in serious heat last year in the fourth round against Holger Rune.
CALF MUSCLES
On Saturday, his run of 12 straight matches without losing a set dating back to Vienna last year was snapped as the inspired Spizzirri stormed back from 4-2 down to take the opener.
He then broke the Italian in the first game of the second set but let the momentum slip with a messy service game. Sinner claimed the next three games and fought off break points before levelling the match.
With the heat pushing past 36 degrees Celsius (97F), Sinner had a trainer work on his calf muscles but was soon reduced to limping between points.
He was warned for a time violation on serve after shuffling over to his box.
"We just need to get through to the end of the set," Cahill told him.
"Even if you walk around, don't worry. We'll take the break."
Sinner lost the next point to fall 3-1 behind but the match's suspension bought him eight precious minutes to regroup.
When play resumed, Sinner broke back at once and held firm until Spizzirri froze on break point at 4-4, dropping serve with a double fault.
Sinner served out the epic, 76-minute set to love, firing down an ace to earn an extended 10-minute break between sets under the heat policy.
Spizzirri was far from done, though.
The 24-year-old raised the pressure on Sinner's serve and broke him in the fourth game of the fourth set with a deft drop-volley.
It was only a fleeting triumph, though, as Sinner broke back immediately with a highlight of his own, chasing down a drop-shot with a cross-court pass.
From there, the Italian was unstoppable as he raced to the finish in a barrage of incredible shot-making.
Spizzirri saved a match point on Sinner's serve but surrendered with a forehand into the net to complete the Italian's great escape.
(Reporting by Ian Ransom in Melbourne; Editing by Peter Rutherford)
