The Mercedes driver was more than three tenths clear at the top of the times on Friday morning despite only using soft tyres to the Ferrari’s ultra softs at the Shanghai circuit.
Raikkonen at least denied Mercedes a one-two, with Valtteri Bottas trailing Hamilton throughout the session and eventually dumped to third, almost half a second behind his teammate.
Williams driver Lance Stroll was the first to record a time 15 minutes into the opening session on an overcast and chilly morning, but Mercedes was comfortably on top at the halfway mark.
Hamilton’s mid-session benchmark of 1m34.962s was set despite a slower middle sector than his previous lap and a slide exiting the final corner.
Times tumbled when the field returned to the ever-improving track, with Fernando Alonso the first to improve, leaping to fifth – one second off the pace at the time – with the first ultrasoft-tyre run of the day in his McLaren.
Nico Hulkenberg, running mediums, swiftly took that place by two tenths of a second, and his works Renault teammate Carlos Sainz rose to third on softs on a 1m35.616s.
More significant improvements swiftly followed, first as Bottas posted a 1m34.661s to briefly jump to the top of the times.
Hamilton, on fresh soft tyres like his teammate, resumed control almost immediately however, lapping almost seven tenths faster as he snuck below the 1m34s barrier on a 1m33.999s.
His next attempt was scuppered by a Turn 11 spin just after posting the best time in the middle sector, and his Mercedes ended up facing the wrong way on the run-off.
Bottas pumped in another two fliers and improved his time but it was not enough to maintain Mercedes‘ one-two.
Raikkonen split the Silver Arrows with an ultrasoft-assisted 1m34.358s to bump Bottas to third, just ahead of Daniel Ricciardo.
Max Verstappen was fifth despite spinning into the gravel on the outside of the corner of the final corner before the start of his first ultrasoft lap.
He resumed but, having flat-spotted that set of tyres, ended up 0.15s slower than his teammate.
Sebastian Vettel ended up a subdued sixth, half a second behind Raikkonen with his best time on ultrasofts, as Haas claimed a comfortable best-of-the-rest victory.
Kevin Magnussen used ultrasoft tyres to take the honours for the American team with the seventh-fastest time, more than four tenths clear of Sainz’s soft-shod Renault.
Romain Grosjean and Nico Hulkenberg (on softs, like Sainz) backed up their teammates in ninth and 10th respectively.
Alonso was shuffled down to 12th behind Pierre Gasly’s Toro Rosso-Honda, which used soft tyres to Alonso’s ultrasofts.
It was a tricky session for McLaren, as Alonso’s teammate Stoffel Vandoorne ended up 18th on the times after a trip through the Turn 10 gravel after losing the rear mid-corner.