Sergio Perez labelled the United States Grand Prix his "toughest ever" after overcoming a drinks bottle issue and a bout of diarrhoea.
The Red Bull driver had excelled across the weekend and was on for a potential pole position at the Circuit of the Americas before spots of rain fell in the final sector on his final run.
In the race, however, Perez was unable to match team-mate Max Verstappen and Lewis Hamilton and ultimately finished 42 seconds behind the Dutchman although managed to keep Charles Leclerc at bay for the final podium spot.
“I think it was my toughest race ever physically,” declared Perez.
"It was a horrible one. I was suffering from some diarrhoea early in the morning for some reason, I don't know so I hydrated myself really well.
"But then, since lap one onwards I ran out of drink and already, from the first stint I was really really struggling massively to make things properly. I was really losing strength and it was really difficult. I think the last 30 or 40 laps were really tough."
Perez's form has picked up in recent races with late rainfall costing a podium opportunity in Russia before registering back to back podiums in Turkey and Austin.
The Mexican is now looking forward to his home race next time out and believes Red Bull will be strong at the venue.
"We got a nice boost and I am looking forward so much to Mexico," Perez added.
"It was a shame I couldn't keep up with Max and Lewis but I was so physically limited but I look forward to Mexico.
"It should be another good track for us."