Nico Rosberg returned to the top of the times in second practice for the Abu Dhabi Grand Prix, outpacing teammate Lewis Hamilton.
The Briton had been quickest in the first session, but Rosberg posted the fastest time so far - 1:41.983 - to finish 0.138 seconds ahead of the world champion.
Both men used the supersoft tyres for their best runs.
Sergio Perez was a surprise third-fastest in the Force India, although over six tenths off the pace set by Rosberg.
Pastor Maldonado was 10th for Lotus.
Unlike in the first session, drivers were quick to post their first timed laps, with Raikkonen setting the early pace after completing his first lap in the 1:43s as the night began to fall at Yas Marina.
Teammate Vettel, meanwhile, started his session by singing happy birthday to his race engineer Riccardo Adami over the radio.
Raikkonen did not stay up on top for long, though, as Rosberg went nearly seven tenths quicker in his first run, then improving even further to dip into the 1:42s for the first time this weekend.
Fifteen minutes in, Hamilton relegated his teammate to second after setting the quickest time in all three sectors to stop the clock at 1:42.524, over three tenths quicker than Rosberg at the time.
Raikkonen was the first driver to switch to the supersoft rubber before the half-hour mark, but the Ferrari driver failed to beat the Mercedes cars and had to settle for third position.
Vettel's first run on supersofts split the Mercedes duo, however, the German falling two tenths short of Hamilton's best. He was soon demoted to third by Ricciardo, also running with the softer compound.
The Mercedes duo were next to try the supersofts, and Rosberg became the first man to dive into the 1:41s, opening a six-tenth gap to Ricciardo.
Hamilton fell short in his run, lapping 0.138s slower than Rosberg.
A superb lap from Perez minutes later elevated the Force India driver to third, albeit still six tenths behind Rosberg.
The main incident of the session came with 30 minutes to go, when Toro Rosso's Carlos Sainz was forced to stop his car due to an apparent engine problem.
Sainz, who had also suffered engine issues in FP1, had to watch the rest of the running from the sidelines.
Perez's day also came to an early finish after he suffered apparent brake problems with some 15 minutes left.
|3||Sergio Perez||Force India||1:42.610||+0.627||23|
|4||Daniel Ricciardo||Red Bull Racing||1:42.647||+0.664||37|
|6||Daniil Kvyat||Red Bull Racing||1:42.798||+0.815||34|
|8||Nico Hulkenberg||Force India||1:42.928||+0.945||35|
|10||Pastor Maldonado||Lotus F1 Team||1:43.431||+1.448||37|
|13||Max Verstappen||Toro Rosso||1:43.662||+1.679||40|
|14||Carlos Sainz Jr.||Toro Rosso||1:43.854||+1.871||20|
|15||Romain Grosjean||Lotus F1 Team||1:43.929||+1.946||27|