Rafael Nadal's vulnerability to late-season injuries resurfaced this weekend as the 19-time Grand Slam champion was forced out of the Paris Masters with an abdominal muscle strain.
The 33-year-old has carved out one of the sport's greatest-ever careers in spite of persistent injury troubles, a pattern which has continued in 2019.
The latest problem has put his participation at both the ATP Tour Finals and the Davis Cup in doubt.
Nadal, who has never won the title at Bercy or the Tour Finals, also withdrew from the Paris Masters before the quarter-finals on his last appearance in 2017 with a knee problem and missed last year's tournament with another abdominal injury.
The world number two, who will usurp Novak Djokovic at the top of the rankings next week, has still only won two ATP titles indoors, a figure at least partly down to his November injury woes.
He had been due to play Canadian youngster Denis Shapovalov in the semis with a final against Djokovic at stake, but announced he was pulling out just minutes before the scheduled start of the match on Saturday.
But Nadal insisted it was not worth the risk, having also suffered with a similar injury 10 years ago.
"I had this issue in the US Open 2009 with a bad experience," he said. "Because I started the tournament with, if I remember, around six, seven, millimetres of strain and I keep playing, I keep playing.
"I finished the tournament with (a) 28-millimetre strain, so have been a big, big thing after that.
"I remember (it) well because I couldn't play semi-finals of the Davis Cup against Israel... So for me, I took almost a month outside of the tennis court, so we don't want to repeat that."
- Long injury history -
Nadal's first injury-enforced absence from the ATP Tour came as a 16-year-old in 2003 when he hurt his elbow in a fall during training and had to miss the French Open -- an event he has gone on to win a record-breaking 12 times.
He has missed at least one tournament in every year of his career since.
Nadal has enjoyed a fantastic 2019, winning both Roland Garros and the US Open to move to within one of great rival Roger Federer on the list for most Grand Slam titles.
But he has been far from an ever-present on tour.
The Spaniard handed Federer a walkover when they were set to meet in the Indian Wells semi-finals before pulling out of the following Miami Open with the same right knee issue.
A left wrist problem forced him to end his Laver Cup halfway through the event in September, and Paris was his first appearance since.
Many pundits consistently predicted Nadal would struggle to enjoy a long career due to his gruelling style of play and he has proved them wrong time and again since.
And he says his latest injury is not due to anything technical.
"I have been serving like this during the whole season. It was not a different movement at all.
"No, that's not an issue."
Nadal said he would fight to be fit for the season-ending championships in London, which start on November 10, until it is "impossible", but will first head home to Mallorca to start his recovery.
Should he miss London, Davis Cup organisers, including Barcelona footballer Gerard Pique, will be desperate for Nadal to be ready for the inaugural finals of the team event, with Federer skipping that week in Madrid.
It will also be a busy 2020, though, for Nadal, with the Tokyo Olympics wedged between Wimbledon and the US Open.