George Russell topped the times ahead of his Mercedes teammate and championship leader Kimi Antonelli in Friday's accident-free opening practice ahead of the Spanish Grand Prix.
The Briton, 66 points adrift of Antonelli in second place in the title race, clocked a best lap time of one minute and 34.077 seconds to outpace the 20-year-old Italian by 0.286sec in a clean session at the challenging new Madring circuit, which Russell has already called "the riskiest track" in the calendar.
"In Monaco, the walls are closer, but because you're going far slower, if you make a mistake, you're not into the wall as quickly, and you can recover it sometimes, a small lock-up," Russell said before the session.
"There's a lot of really fast corners, but the barrier is kind of like coming back onto the track. So, if you are to go wide and hit the wall, you're not hitting it at the same angle as the car is going. The wall is sort of coming in at you."
The Ferraris of Charles Leclerc and seven-time world champion Lewis Hamilton were third and fourth ahead of Red Bull's four-time champion Max Verstappen, reigning champion Lando Norris of McLaren and Racing Bulls' rookie Arvid Lindblad.
Oscar Piastri was eighth in the second McLaren ahead of Nico Hulkenberg of Audi and Liam Lawson in the second Red Bull.
Despite many forecasts of red flags and crashes, the drivers showed a high degree of respect for the high-risk track and drove with measured professionalism, easing into learning the circuit and increasing their commitment and speed.
A big crash during an earlier Formula Two race, that saw Thai driver Tasanapol Inthraphuvasak climb unhurt from his blazing car, served as notice of the perils ahead.