With Roger Federer a point away from going two sets down in his French Open quarter-final, his wife Mirka was spotted in the players's box sitting with her palms pressed together - perhaps praying for some divine intervention.
To many tennis fans Federer is already a god when he is let loose on a rectangular surface but Argentine Juan Martin Del Potro made him look like a mere mortal for an hour and 39 minutes on Tuesday.
"Just trying to figure out how to play a guy who returns from so far back on a slow court. Do you try to serve through him? Which I tried - didn't work," explained Federer following the 3-6 6-7 6-2 6-0 6-3 win which kept alive his dreams of a 17th grand slam title.
With his dark hair tied back in a bandana and kitted out in a canary yellow shirt and grey shorts, Del Potro buzzed around Suzanne Lenglen Court stinging Federer with vicious winners.
Such was Federer's frustration at being broken for the fourth time in the match, when the Swiss netted what appeared to be an easy forehand, he flashed a rare burst of anger.
Narrowing his eyes, he took a ball out of his pocket and whacked it ferociously against the net, as if to say: "How dare you block my shot?".
It failed to have the desired effect for the rest of the set, as Del Potro went about his task as a man on a mission determined to execute a winning game plan.
In fact, Del Potro had made no secret what his tactics would be.
"I have to play an unbelievable match, try to take my opportunities, serve at a 100 percent, try to play winners with my forehand, with my backhand, and force him to raise his game," Del Potro, who has had his left knee heavily strapped throughout the tournament, said on the eve of the showdown.
"I don't like to run too much, so I will try to be more aggressive than his game and look for unbelievable shots."
For two sets he was true to his word as Federer's chances of reaching a record-equalling 31st grand slam semi-final appeared to be sinking fast as he drowned under a hail of "unbelievable shots" flying off Del Potro's racket.
The one thing Federer, however, was banking on was the belief that: "The road to victory is much longer and it's not a sprint, it's a marathon."
A double fault from Del Potro handed Federer a 2-0 lead in the third set, and from then on it seemed as if a re-energized Federer had suddenly turned from Haile Gebrselassie into Usain Bolt.
The Swiss swept through the next two sets at lightning fast speed, flicking backhand winners here and forehand winners there, while Del Potro lost his spark.
The fireworks of the first two sets had gone and he lumbered around court, increasingly troubled by his dodgy knee.
He won just eight points during the fourth set whitewash and even after taking some painkillers and having his knee re-strapped before the start of the fifth, he failed to get going.
After three hours and 15 minutes, a bouncing netcord ended Del Potro's challenge and a hugely relieved Federer was off to get ready for a semi-final date with Novak Djokovic.
(Editing by Toby Davis)