Using soft compound tyres, Raikkonen set a best time of 1m20.960s just over an hour into Tuesday afternoon's running – narrowly bettering Hamilton's session-topping morning effort of 1m20.983s, which was set using supersofts.
Hamilton's effort was still good enough to finish the day second overall, with Valtteri Bottas taking over driving duties for Mercedes for the afternoon.
The 63rd single-seater designed and built by Scuderia Ferrari to take part in the Formula 1 World Championship is born out of a regulation change that is without precedent in this category of motor sport.