Red Bull's Max Verstappen had a comfortable advantage over Mercedes' George Russell.
Verstappen was quicker than Russell as the final race weekend of the season started.
Lewis Hamilton headed Russell to a Mercedes one-two in the first session.
Hamilton was fourth in the second practice session.
World champion Verstappen sat out the first session so Red Bull could comply with the rules governing young driver testing, but he was up to speed in the second.
When cars run with full tanks, he was the fastest on the single lap simulation runs.
Russell was about a third of a second off Verstappen and Leclerc was a further half a second behind. Hamilton's run was disrupted by traffic, but it appeared to be the same as Russell's.
Verstappen said that the car had no problems. The car was working well after we tried as few things as possible. I am pleased with that.
It was expected that Red Bull would be quicker than us this weekend, according to Hamilton. Hopefully, we can put on a good fight.
"It felt fast but Red Bull just had the legs on us - 0.2 seconds ahead on a single lap and on the long run maybe further," Russell said. We look reasonable.
We can fight for the top three in qualification, but who knows where we'll go on Sunday?
Leclerc is competing for second place in the drivers' championship with Red Bull'sSergio Perez.
Whoever wins the grand prix will win the position.
It seems a meager prize for Leclerc after his early season promise collapsed in a torrent ofFerrari errors and reliability failures, but two separate team orders disputes last weekend in Brazil revealed that both cared
After agreeing to swap their cars on the morning of the race, they decided against it on the last lap.
The eruption at Red Bull when Verstappen refused an order to let Perez by for sixth place was more disappointing.
Verstappen's admission that he acted in that way because of something that happened in the past dominated the race weekend in Abu Dhabi.
Multiple sources have said that Verstappen believes that Perez crashed deliberately in the final stages of Monaco Grand Prix qualification.
The Dutch driver was left fourth on the grid behind Perez, who went on to win the race, because of that.
There is a crisis at Red Bull. Verstappen said in a statement that he made his feelings known at the previous race in Mexico, and the team admitted to mistakes in handling the race in Brazil.
The mistake was not to discuss with Verstappen before the race that they wanted him to help Perez, which he says he will do this weekend.
According to sources within Red Bull, Perez admitted to crashing in Monaco for the sake of the team. The Mexican says that information is incorrect.
Perez said he regretted some of the things he had said about Verstappen after the race.
A number of young drivers were given opportunities during the first practice session.
In his last grand prix before retirement, Sebastian Vettel was fastest in the Red Bull, but he was behind the fastest man in the race, Lawson.
Everyone on the teams and the media have been asked to join him for a photo after the race, before he runs or walks the track.
Robert Schwarzmann was seventh fastest in Sainz's car, followed by McLaren's Daniel Ricciardo, Alfa Romeo's Valtteri Bottas, and Williams driver Alex Albon.
If he gets enough licence points in the Formula 2 finale this weekend he will graduate to F1 with Williams.