Ricciardo's time of 1:18.455 was 0.183s quicker than Ferrari's Sebastian Vettel, as less than half a second covered the leading six drivers, and the Australian is hopeful of carrying his pace through to Saturday.
"Today was good, it was certainly a positive day, to replicate the same pace as this morning in the afternoon [was] positive. I'm sure the other teams will bring a bit more tomorrow, but I also think we have a bit more to find".
In the morning, Ricciardo was 0.234 seconds quicker than Raikkonen and 0.372 ahead of Hamilton on a Hungaroring circuit that proved slippery despite warm weather conditions.More news: Bomb-sniffing dog gets final salute
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With Robert Kubica testing for Renault next week, amid speculation about what once seemed an impossible comeback after the Pole partially severed his forearm in 2011, Palmer needs to do something special.
Palmer brought an early end to the session when he ran wide at Turn 4, driving over the exit kerb, which shattered his front wing, caused a puncture and scattered debris across the track. He went to the circuit medical centre but was reported to be fine.