Mystery surrounds the fitness of Alex de Minaur as he prepares for the biggest match of his career.
The Australian No.1 faces a Wimbledon Centre Court showdown with seven-times champ Novak Djokovic, with a debut grand slam semi-final place at stake.
But the 25-year-old is sweating on a hip injury incurred while winning the final point of his fourth round match against Arthur Fils.
De Minaur is due on court Wednesday afternoon in London (early Thursday morning AEST). His match is scheduled after the highly-charged women's quarter-final between Ukraine's Elina Svitolina and Moscow-born Elena Rybakina, who represents Kazakhstan (Wednesday 2230 start AEST).
However, on Tuesday he did not practice on either the indoor or outdoor courts at Wimbledon. It is possible he had a hit elsewhere, but there are a limited number of indoor courts in the area and constant rain made outdoor training unfeasible.
His camp were tight-lipped, unwilling to discuss either his fitness or training activity.
De Minaur pulled up as he secured a tense four-set victory over Fils, concluding with an angled stop volley at the net after a forehand set-up shot.
There were no celebrations from him, which may have been as he was simply relieved to win after blowing a two-set advantage at the same stage in 2022, but could also have been because he knew, in that instant, he was injured.
He walked stiffly to his chair, looking more like he'd lost than won the match, then sat deep in thought for a few minutes.
At the time he said, "I'll be alright. I'll find a way. You can count on me going out there, trying my hardest and playing my heart out."
A few hours later he added, his hip was "a little bit 'ginger'" but "it's probably a little bit of a scare more than anything".
That the 25-year-old will give it his all can be guaranteed, but for a player whose game is so dependent on speed and movement, taking on Djokovic restricted by injury would be a huge handicap.
As it happens Djokovic is still working back to full fitness himself after a knee operation on a torn meniscus barely a month ago.
However, his mobility has improved as the championships have gone on, as he confirmed after his last-16 win over Holger Rune.
"The knee has been really - knock on wood - really good. It did not react negatively to those few slips that I had today.
"I've been really experimenting (with movement) because of cautiousness because of the knee.
"The first couple rounds I was still not maybe willing to go on extreme balls and slide and make splits, but last few matches I've done it."
Grand slams are gruelling and Wimbledon has the added factor of grasscourts. In a fortnight as damp as this they can get wet outdoors and slippy under the roof when the air becomes humid.
There have been several injury-related withdrawals and losses this Wimbledon, most notably from an Australian viewpoint that of Thanasi Kokkinakis against Lucas Pouille after a bad fall.
Pouille then quit before he even got on court against De Minaur.
In addition Grigor Dimitrov, Hubert Hurkacz, Madison Keys and Anna Kalinskaya are among those to have quit during matches while Alexander Zverev was troubled by the impact of a previous fall in his fourth-round loss to Taylor Fritz.
