CARLOS ALCARAZ appeared to have mystery method of keeping cool during his US Open quarter-final win over Alexander Zverev.
The world No1 defeated the German 6-3 6-2 6-4 to book his spot in the next round.
Eagle-eyed fans saw Carlos Alcaraz rub a mystery substance on his armsCredit: Nine
The world No1 is through to the semi-finals as he looks to defend his US Open crownCredit: EPA
Temperatures in New York have hit a whopping 35 degrees/95 Fahrenheit this week.
And Alcaraz seemed to put a mystery substance on his skin to prevent sweating during the match.
The Spaniard was spotted rubbing what some believed was sawdust on his arms to combat the heat.
Australian commentator Brenton Speed said: “This is interesting, sawdust being utilised here to slow down the sweating going on.”
Fellow pundit and doubles Grand Slam legend Todd Woodbridge joked: “You could almost see him going up to the parallel bars at the Olympics.”
Fans were also left baffled as one wrote on social media: “What kind of juju is Alcaraz putting on his arms?”
In an attempt to deal with the soaring heat at Flushing Meadows, organisers have shut the roofs and put air conditioning on inside the Arthur Ashe and Louis Armstrong stadiums.
Alcaraz, who won the title last year, will play 2021 champion Daniil Medvedev in the semi-final.
The Russian complained about the conditions during his last-eight encounter with compatriot Andrey Rublev.
Medvedev moaned on court: “One day a player gonna die and they gonna see.”
He added post-match: “Usually there is not one that suffers so it’s tough for both of us.
“Honestly, at the end of the first set I kind of couldn’t see the ball anymore.
“I kind of played with sensations. Just tried to go for it, tried to run, tried to catch the balls and he did the same.
“We were tired all the time. So yeah, brutal conditions and super tough to win.”