Abu Dhabi: Sebastian Vettel shook off any last vestiges of a hangover on Friday when he clocked the fastest time ahead of Red Bull team-mate Mark Webber in second free practice for the Abu Dhabi Grand Prix.
The newly-crowned quadruple world champion, who is seeking to secure his seventh successive victory, was third quickest in morning practice, but responded in style in the afternoon.
His fastest lap time of one minute and 41.335 seconds lifted him one-tenth of a second clear of Webber in a session run in cooling conditions and under dazzling floodlights at the ultra-modern Yas Marina Circuit.
The ambient temperature dropped by 14 degrees during the session after recordings of 35 degrees Celsius for the air and 46 for the track earlier in the day.
Lewis Hamilton, who has always enjoyed and impressed at the Yas Marina, was third fastest for Mercedes ahead of Kimi Raikkonen in the leading Lotus, Nico Rosberg in the second Mercedes and Sergio Perez of McLaren.
Vettel, who admitted he felt sick after a night of celebrations in the hotel bar following his triumph in last Sunday's Indian Grand Prix, once again looked to be in utter command.
Afterwards, he said he felt that the Lotus team appeared to be the biggest threat to his winning streak.
"It will be the usual suspects, to be honest," he said, when asked who might emerge as his main rivals.
"Lotus is exceptionally quick, especially come Sunday, and may be able to pull off strong pace later on in the stint -- so we will have to keep an eye on them.
"Mercedes are strong on one lap for tomorrow (qualifying)."
He admitted that he had little idea about Ferrari's potential.
Two-time champion Fernando Alonso was 12th in the morning and then only eighth in the afternoon for the Italian giants.
"I haven't seen much of Ferrari," said Vettel. "Judging the long-run pace is difficult."
Rosberg, who was second in India last Sunday, said he felt confident that Mercedes were capable of being second to Red Bull.
"This morning, it was not possible to learn much, but this evening was very important because the conditions are exactly what they will be in qualifying tomorrow and in the race," said the German driver.
"As always, the aim is to be best of the rest behind Red Bull because they are untouchable and it's looking good for now."
Hamilton endured a difficult Friday despite being the best-placed non-Red Bull.
He suffered a differential problem, but said he felt confident.
"The long run is always interesting," said Hamilton.
"It's difficult to know what the car is going to do and as the car gets cooler, it goes into more understeer and it's about how much more or less front wing you need.
"That's the big challenge -- just trying to balance how fast you go to how much you save the tyres to make them last longer."
Behind the top six, Jenson Button was seventh in the second McLaren ahead of Alonso and Nico Hulkenberg of Sauber with Felipe Massa 10th in the second Ferrari.
Lotus driver Romain Grosjean, who was fastest in morning practice, finished up down in 12th after twice being hit by braking problems.
He arrived in Abu Dhabi fresh from three straight podium finishes.
For McLaren, this weekend -- and the following last two races of the year -- present the team with a challenge.
The last time McLaren went through a season without a podium finish was back in 1980.
The team's best result this year is fifth -- by Button in China and Perez last time out in India.
The last team they went through a season without a top four finish was in their inaugural season of 1966.