Lotus's Finnish stand-in, replacing Raikkonen at short notice after the 2007 world champion pulled out of the last two races to have back surgery, qualified an impressive eighth for his first race since 2012.
"I've done everything I can to step into his shoes for this weekend and I've even worn his fireproof underwear. I hope it was washed," Kovalainen told the team website.
It was the first time since he was at McLaren in 2009 that he had made the top 10 and his next task is to score points again.
United States Grand Prix
Williams rubbishes Maldonado's claims
17/11/2013 AT 07:46
Kovalainen, who arrived too late for a news conference he was scheduled to appear in at the Circuit of the Americas on Thursday, said he had been given a 'smooth landing' at the team he last drove for when they were Renault.
"Obviously they like working with a Finnish driver," he said.
"I haven't spoken to Kimi as he's busy recovering from his operation, and knowing Kimi he might wind me up about the car."
United States Grand Prix
Kovalainen thinks he met expectations
17/11/2013 AT 00:12
United States Grand Prix
Bottas reckons he underperformed
16/11/2013 AT 23:58