Manama, Bahrain: Charles Leclerc, in just his second Grand Prix weekend, topped the times ahead of his team-mate Sebastian Vettel as Ferrari dominated Friday's opening free practice for the Bahrain Grand Prix.
With track temperatures rising to 48 degrees Celsius (118 degrees Fahrenheit), the Ferrari duo comprehensively outpaced Mercedes' Valtteri Bottas and defending five-time champion Lewis Hamilton, who were nine-tenths and 1.2 seconds adrift in third and fourth.
Max Verstappen was fifth ahead of his Red Bull team-mate Pierre Gasly, Carlos Sainz of McLaren, Nico Hulkenberg of Renault, Daniil Kvyat of Toro Rosso and Kimi Raikkonen in a Alfa Romeo.
There were few major incidents in the session until a late collision involving German driver Hulkenberg and the Italian Antonio Giovinazzi, in the second Alfa Romeo, in the closing minutes.
Neither driver was hurt after they banged wheels as Giovinazzi tried to find a way past the Renault.
Leclerc, 21-year-old from Monaco, was in nerveless form as he outpaced Vettel by two-tenths of a second.
The newly-bearded Bottas had earlier been the fastest man on the track as he built on his confidence-boosting victory at the season-opening Australian Grand Prix while Hamilton, struggling with rear balance to his car, toiled in pursuit of the Finn until the Ferrari pair came out to set the real pace.
Bottas' early form endorsed the view that he is a changed man this year as he bids to prevent a repeat of 2018 when Hamilton took the drivers' title comfortably and the Finn was reduced to acting as his wing man and endured a winless season.
Bottas said he had decided on a winter "re-set" to give him more confidence and aggression, but Hamilton, often a slow starter to a season, said he saw no difference.
"I work with the guy and he's the same guy he was last year, so no difference for me - except he has a beard," said Hamilton.
"But time will tell, I guess. I never thought he was a weak person anyway. I've always seen him as a strong character."
Bottas said his change went beyond his facial hair.
"My preparation over the winter and the way I feel and think about things have changed, but it's quite difficult to explain. I feel different from the years before."