Lando Norris stole an early advantage in Formula 1's title decider after he saw off world championship rival Max Verstappen by just eight thousandths of a second in first practice for the Abu Dhabi Grand Prix.
Norris, who has to finish third on Sunday to be assured of his maiden title, led the way, narrowly ahead of Verstappen, with Ferrari's Charles Leclerc third.
Oscar Piastri, the other title protagonist, watched on from the McLaren pit-wall with Pato O'Ward, among nine rookie drivers in mandatory action, deputising for the Australian.
Piastri will be back in his McLaren for the second session which gets under way at 17:00 local time (13:00 GMT).
Norris heads into Sunday's 24th and concluding round at the Yas Marina Circuit guarding a 12-point lead over four-time world champion Verstappen.
Piastri is 16 points behind his McLaren teammate with just 25 points to play for in the season finale.
Verstappen has taken five victories from his last eight appearances to propel himself into the championship fight.
However, the in-form Red Bull driver had to settle for second in the opening running of the weekend, with Norris setting the early pace.
Verstappen was also upset with the handling of his Red Bull.
"I think something is broken on the car," said Verstappen on the radio.
"Where are the main areas of issue?," his race engineer, Gianpiero Lambiase, asked.
"It is everywhere now," replied the Dutchman.
Kimi Antonelli finished fourth for Mercedes, two places ahead of teammate George Russell, as the Silver Arrows look to cement second place in the constructors' championship. Sauber's Nico Hülkenberg split the Mercedes pair in fifth.
