Oscar Piastri topped championship leader Lando Norris in practice for the Qatar Grand Prix, with Max Verstappen only sixth.
Norris heads both Piastri and Verstappen by 24 points heading into the penultimate round of the title race in Doha.
Piastri finished just 0.058 seconds ahead of McLaren teammate Norris in the sole practice session of the weekend, with qualifying for Saturday's sprint race to follow later on Friday.
Verstappen won emphatically in Las Vegas six days ago but he complained about the handling of his Red Bull throughout the one-hour session - turning the air blue with an expletive to describe his gear shifts and and then calling his exit from the sixth corner a "disaster" -- and finished 0.580 sec off the pace.
Fernando Alonso was third for Aston Martin, with new team principal Adrian Newey on the pit wall and watching on, one place ahead of Williams' Carlos Sainz.
Isack Hadjar finished fifth for Racing Bulls, while Lewis Hamilton was only 12th, nearly nine tenths back and four places behind Charles Leclerc in the other Ferrari.
Norris had hoped to arrive in the Middle East with a commanding 30-point lead over Piastri and 42-point advantage to Verstappen, but that all changed following his disqualification from second place in Las Vegas for running an illegal car.
That decision has handed the initiative to Verstappen - a winner of four of the past eight races - but the Red Bull driver appeared down on speed.
Qualifying for Saturday's 25-lap dash to the chequered flag which takes place at 2030 local time (1730 GMT).
Information from PA contributed to this report.
