Valtteri Bottas topped the times for Mercedes ahead of Red Bull's Max Verstappen and his Mercedes teammate Lewis Hamilton in Friday?s opening free practice for the Abu Dhabi Grand Prix.
The Finn, who is assured already of finishing second behind six-time champion Hamilton in this year?s title race, clocked a best time of one minute and 36.957 seconds to outpace Verstappen by half a second and Hamilton by six-tenths.
Bottas, who announced the break-up of his marriage on Thursday, will start from the back of the grid on Sunday regardless of how he does in qualifying after being sanctioned for taking a new power-unit.
He clocked his best lap on a set of medium tyres midway through a session stopped twice for red flags following a blown engine in Daniel Ricciardo?s Renault and a late crash by Ferrari's Sebastian Vettel.
The four-time champion Vettel had arrived late at the circuit on Friday morning following the birth of his third child, a son, on Wednesday.
Red Bull new boy Alex Albon was fourth, Vettel fifth and Romain Grosjean sixth for Haas ahead of Charles Leclerc in the second Ferrari, Kevin Magnussen in the second Haas, Alfa Romeo?s Antonio Giovinazzi and Renault?s Nico Hulkenberg who is set to start his final Grand Prix with the team.
Bottas dominated the session from the start and was only replaced briefly early on by Hamilton before the stoppages on a hot day of blue skies at the Yas Marina circuit.
Ricciardo's engine failure dumped a lot of oil on the track, which led to a 10-minute clean-up before the action resumed and Vettel spun backwards into the barriers.
Williams's George Russell took part in the session and wound up 20th despite doubts about his fitness due to illness. He went through a medical check before taking part.
Hamilton ran briefly in the session with number one on the nose of his car and, when asked earlier about Bottas' private predicament, said that balancing the demands of racing with a full private life was dificult.
He congratulated Vettel on the new addition to his family while sympathising with Bottas following the split with wife Emilia, an Olympic swimmer and a horse show jumping rider, after three years' marriage.
"It?s similar to most sportsmen and women, but it may actually be slightly different in that we are away for crazy amounts of time," he said.
"I for one also find that incredibly difficult, with your goal to be as competitive as you can be, but there are those who manage it -- like Seb."
Mercedes' Finnish driver Valtteri Bottas in the first practice session for the Abu Dhabi grand prix