LEWIS HAMILTON and team-mate George Russell were both pulled from their planned media duties after "overheating" during the Singapore Grand Prix.
Mercedes boss Toto Wolff admitted it was "painful" to see the Silver Arrows place fourth and sixth.
The Marina Bay street race is usually the most physically-demanding of the Formula 1 season. owing to Singapore's heat and humidity.
Wolff told how Hamilton, who placed sixth after starting the race from P3, fell ill in the immediate aftermath of the 62-lap race.
And Russell, who finished fourth, was heard on team radio in his car during the closing stages saying "it's like a sauna in here".
The British Mercedes pair didn't carry out their usual post-race media duties on medical grounds.
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A spokesperson for the team said: "Unfortunately neither George or Lewis will be attending the media pen this evening as they recover from the exertions of this evening's race."
Team Principal Wolff told reporters: "They are both suffering from overheating.
"But they are fine now. They put themselves in an ice bath and I think that helped a bit."
The race itself had proved a disappointing one for both Hamilton and Russell from the second row.
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The Mercedes duo were split by Ferrari's Charles Leclerc, who recovered from ninth on the grid to overtake Hamilton and finish on the lead Mercedes' tail.
On the race, Wolff said: "It was a really painful evening.
"It's not about when you look at the positions we are fourth and sixth, that's not good especially when you are starting third and fourth."
"We struggle at the moment with tracks that are hot and are tough on traction. It was here and it was Baku.
"But this is no excuse, it's just at the moment now what we expect from ourselves because if your quickest car is a minute behind the leader it's just difficult to accept."
The Mercedes' W15 was not a match on race pace for the two McLarens, which finished first and third.
While standings leader Max Verstappen finished second behind title rival Lando Norris with six races remaining.