Sebastian Vettel and Lewis Hamilton finished on top in Friday's respective practice sessions ahead of the Abu Dhabi Grand Prix.
Ferrari driver Vettel was 0.12 seconds quicker than Hamilton in practice one on Friday ahead of the season-ending race of 2017.
I think it will be close also tomorrow.Sebastian Vettel
But Hamilton, who sealed up his fourth Formula 1 drivers championship crown in Mexico two races ago, came out on top in the afternoon as he was 0.149 seconds quicker than the German.
Red Bull's Daniel Ricciardo was in third in P2, 0.164secs further back, while his team-mate Max Verstappen followed Ferrari's Kimi Raikkonen and Mercedes' Valtteri Bottas, in sixth place and 0.9 secs slower.
Looking ahead to Saturday's practice and qualifying ahead of Sunday's race, Vettel said: "I think it will be close also tomorrow."
His Ferrari team-mate, Raikkonen, added on Sky Sports: "It is only Friday, obviously early days. The car could have been better in some places."
Vettel is 7/1 to follow up his win in Brazil last weekend and end 2017 with a win, while Hamilton is priced at 1/1 to cap of his title-winning season with the chequered flag at the Yas Marina Circuit on Sunday.
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