Highly experienced F1 engineer Mark Slade says retired 2007 world champion was in one way "the best driver I’ve ever worked with".
Slade, with a wealth of experience gathered at McLaren, Renault and Mercedes, moved recently to Haas where he now works with Kevin Magnussen.
But he is most famous for engineering Raikkonen’s cars, even though he also worked with world champions Mika Hakkinen, Fernando Alonso and Michael Schumacher.
"For me, Kimi’s the best driver I’ve ever worked with to set up the car," he told Motorlat.
"He’s absolutely phenomenal. His feel for changes was just astonishing.
"You would make a change, and he would tell you that was better here and worse here. He could tell you ’if you can sort this out, I’ll go quicker, so you just concentrate on sorting that out’.
"I think a lot of drivers find it more difficult to be that specific," Slade added.
He also said Raikkonen had a sixth sense for when something was wrong with his car.
"Obviously he wouldn’t be able to specify what it was, but if you looked and couldn’t see anything to start with, you kind of had to look again," said Slade. "The chances were that there was something wrong."
And he said that even after Raikkonen had a break from Formula 1 and returned with Lotus in 2012, the Finn was still "so fast".
"It was a really enjoyable time, and he was just a delight to work with," said Slade. "He was just great - and on it all the time."