Jannik Sinner is out of the French Open in the biggest shock of the tournament so far after struggling with injury in a five-set loss to Juan Manuel Cerundolo in the second round in sweltering Paris conditions.

World number one Sinner was the heaviest favourite for the men’s title since the great Rafael Nadal in 2009, with no-one coming close to challenging him on the clay in recent weeks.

Sinner was bidding to complete the career Grand Slam at Roland Garros, and few expected him to fall short – but just as Nadal suffered an early exit 17 years ago, the Italian will now have to wait for another chance at Paris glory.

Sinner was two sets and 5-1 up before a remarkable change of momentum.

The 24-year-old appeared laboured on court with a dejected expression as he lost the next three games, including 11 straight points, before calling for the trainer.

Sinner could be heard saying he felt “dizzy” and like he “wanted to vomit” and took a mid-game medical timeout before returning to court.

After dropping the third set, Sinner failed to regain his fitness as Argentina’s world number 56 won 3-6 2-6 7-5 6-1 6-1.

It is a bitterly disappointing way to exit the tournament for Sinner, whose favourite tag was enhanced further with defending champion and great rival Carlos Alcaraz missing with injury.

With 24-time Grand Slam-winner Novak Djokovic also nearing the end of his illustrious career, fitness was expected to be one of the biggest obstacles to Sinner’s bid for glory.

Paris has seen unseasonably hot weather, with temperatures topping 34C, and Sinner has struggled previously in extreme heat.

Sinner was also on a 30-match winning streak, having won five Masters 1000 titles in a row over the past three months on hard and clay courts.

He cramped badly in temperatures close to 40C at this year’s Australian Open, and admitted he “got lucky” when the heat rule was enforced in his third-round match against Eliot Spizzirri in Melbourne.

After opening his campaign against Clement Tabur in Tuesday’s cooler night session, Sinner was first on court against Cerundolo in a rare move by Roland Garros organisers.

The last time a men's number one opened proceedings on Court Philippe Chatrier before the semi-final stage was 10 years ago, when Novak Djokovic beat Tomas Berdych in the quarter-finals.

Although Sinner seemed to benefit initially from the early start, the physical issues that have hampered him previously in extreme heat resurfaced.

After comfortably winning the first two sets where Sinner offered up only one break point opportunity, the match turned on its head as he closed in on victory.

Where Sinner had previously controlled the rallies with power and accuracy from the back of the court, his strokes were suddenly became 10mph slower.

Sinner was left walking dejectedly around the back of the court, shaking his legs out as he struggled to generate power and chase down Cerundolo’s shots.

After going three break points down when serving for the match at 5-4 up, Sinner doubled over and called for the trainer.

He described feeling nauseous and took an off-court medical time-out but he was a shadow of his usual self when he returned.

Sinner took lengthy off-court breaks at the end of each set, but continued to struggle, walking gingerly, wincing and hunching over his racquet between points.

Cerundolo deserves credit for staying calm, winning the third and fourth set with ease before taking a 4-0 lead in the fifth.

The crowd tried to lift Sinner throughout – as did his coaching team who shouted words of encouragement between games – and he had a brief respite when he held serve to win only his second game of the past 18.

But it was in vain as Cerundolo won the next game on Sinner’s serve to end his career Grand Slam dream for another year.

The defeat was Sinner’s first since February and his first on a clay court this season.

The defeat throws the men’s draw wide open, with Djokovic now having his best chance in recent memory at a record 25th Grand Slam.

Cerundolo’s reward for beating Sinner is a third-round tie against Spanish world number 69 Martin Landaluce, who also came through in five sets. (BBC)

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