Volkswacht Bodensee - Fishing helped Altmaier down Sinner in 5-hour 26-minute French Open epic

Altmaier, the world number 79, twice staved off match points late in the fourth set before eventually prevailing 6-7 (0/7), 7-6 (9/7), 1-6, 7-6 (7/4), 7-5 on Court Suzanne Lenglen on his fifth match point.

"A week before coming here I was fishing with my dad to calm down a little bit," he said. "So I think, yeah, in the fifth set maybe the experience of fishing a little bit helped me."

Altmaier and Sinner also played a five-set match in the US Open first round last year, when Sinner was the victor.

"We've had historic matches with so many match points," added Altmaier. "I don't know if you can call this a 'historical' match, but I think it was one to remember."

The longest ever match at Roland Garros remains the six hours and 33 minutes it took Fabrice Santoro to beat fellow Frenchman Arnaud Clement in 2004.

Thursday's clash was the longest since Lorenzo Giustino beat Corentin Moutet in six hours and five minutes in 2020, which was shorter only than Santoro and Clement and came before the introduction of final-set tie-breaks.

Altmaier will take on Grigor Dimitrov for a spot in the second week.

He has enjoyed a strong run of results on clay this season, including reaching the Madrid Open quarter-finals as a qualifier last month, having been ranked as low as 113th in April.

"It means a lot. I think personally in the process of the last seven weeks it's been really good. I've been really working really hard," Altmaier added.

"Really being responsible for some things off the court, on the court. This is showing off in a very short-term, and I think this is beautiful."

It was Altmaier's second win against a top-10 opponent after his victory over Matteo Berrettini in the 2020 French Open third round.

The defeat ends an up-and-down clay-court season for Sinner, who withdrew injured from the Barcelona Open before losing to Francisco Cerundolo in the Rome last 16.

"I feel like the season is going good. I played a lot of matches. But for sure the last two tournaments were not that what I was expecting," said the world number nine.

"It is a tough one to swallow, but I keep going."

The 24-year-old Altmaier twice averted defeat when Sinner was serving for a last-32 place in set four before winning the third tie-break of the match.

Altmaier, who reached the fourth round in 2020, broke in game seven of the decider but then also failed to serve it out.

He immediately gave himself another chance, though, and this time crept over the line as he secured a surprise win on his fifth match point after a thrilling final game in which he also saved three break points.

J.Bergmann--BTB