The Finn returned to the sport last season, after two years splitting his time between the World Rally Championship and NASCAR, and despite failing to secure a win, finished the season third in the standings.
His Lotus team's car was the standout performer during the weekend's testing in Jerez, as he finished fastest on the final day, to back-up team-mate Romain Grosjean's leading time on Friday.
The F1 circus now heads to Barcelona for the final test meeting before the start of the season and Raikkonnen is confident he'll be able to continue his form into Catalonia and beyond.
"We are happy with what we achieved, it was a pretty good test," he said. "We will see in the first race, but so far it is pretty OK. I think the car is a bit better everywhere.
"The Lotus was good in Barcelona last year, and I don't see why we won't be OK [this year]. We're pretty happy with how things are going."