Charles Leclerc says he feared Romain Grosjean was dead following the Frenchman's fiery crash in Bahrain.
Grosjean spent three nights in the hospital before being discharged on Wednesday morning after receiving treatment for burns on both hands
Leclerc, speaking with BBC Sport, said: "I saw the crash in my mirrors, was aware straight away that it was extremely serious and I thought the worst straight away."
"Unfortunately, there was no news until I got back into the pits and got out of the car to finally know he was out, which I couldn't really believe, especially because coming into Turn Nine, I saw the flames and the fire.