Red Bull's Max Verstappen made a perfect start on Friday in practice for a home Dutch Grand Prix that could bring the double Formula One world champion a record-equalling ninth win in a row.
The 25-year-old, who leads Mexican team mate Sergio Perez by 125 points after 12 of 22 races, lapped Zandvoort's seaside circuit with a best time of one minute 11.852 seconds on soft tyres in the first session.
Aston Martin's Fernando Alonso was second quickest, 0.278 slower, with Mercedes seven times world champion Lewis Hamilton third.
Perez was fourth on the timesheets, 0.471 slower than his team mate, with Williams' Alex Albon fifth and Lando Norris sixth for McLaren.
Dominant Red Bull have won every race this season, and the last 13 in total, while Verstappen is chasing his third successive Dutch Grand Prix win in front of the packed grandstands full of orange-clad fans.
Verstappen went across the gravel at turn 11 on his final lap of the session, without damage.
Haas's Nico Hulkenberg spun off into the gravel, nudging the tyre wall with his front wing, with 19 minutes to go and bringing out the red flags with the car stuck.
"The only problem is this was the new front wing and we don't have a lot of them," team boss Guenther Steiner told Sky Sports television.
"The one thing that shouldn't be damaged is the front wing and we have to see if we can repair it or not. I think the chances are low to repair this front wing but otherwise we got away pretty easy."
Steiner said Haas had only one spare of the new front wing and had to decide whether to risk using it in second practice or keep it for Saturday.
Aston Martin's Lance Stroll, who skipped media duties on Thursday due to an infection, failed to set a lap time after reporting a 'funny noise'. The team said they were investigating a suspected power unit issue.
Israeli Robert Shwartzman replaced Spaniard Carlos Sainz at Ferrari for the session, in line with the regulations requiring teams to run young drivers during the season, and was 19th and 2.951 off the pace on medium tyres.
Ferrari's Charles Leclerc was 16th.
(Reporting by Alan Baldwin in London, editing by Toby Davis)