Ferrari's Carlos Sainz pulled out a flyer in the latter part of Friday's first practice at the Hungaroring to top the timesheets by 0.130s from Red Bull's Max Verstappen.
Behind the two front-runners, Charles Leclerc was third while McLaren's Lando Norris clocked in fourth.
Mercedes' George Russell and Lewis Hamilton ended the incident-free session respectively P5 and P7, the pair sandwiching Sergio Perez.
The Hungarian Grand Prix weekend kicked off yesterday with the bombshell news of Sebastian Vettel's retirement at the end of the season. And the Aston Martin driver was the first man out when the light turned green at the end of the pitlane.
Traffic was dense at the outset of the session which started under a cloudy sky, with air temperatures at 32.0°C and track temps sitting at 56.0°.
No prospect of rain but it's expected to be a very different story tomorrow and possible on Sunday, with rain forecasted to shove a wrench in the works.
Birthday boy Fernando Alonso, who turns 41 on this day, was also among the most assiduous runners early on, as was Alfa Reserve Robert Kubica who took over Valtteri Bottas' C42 in first practice.
Another point of interest at the start of the session was Haas' long-awaited updated car, a single example of which is in the hands of Kevin Magnussen this weekend.
Ten minutes in, Leclerc was top of the timesheet followed by Verstappen, giving an early edge to Ferrari which the Dutchman expects will be very strong this weekend.
Sainz picked up from his teammate at the front while Perez slotted in fourth to complete a Ferrari/Red Bull quartet, with all four drivers setting their early time on the soft tyres.
Both Russell and Hamilton took their time to join proceedings but on their first attempt on the soft tyre, the Mercedes pair clocked in respectively P2 and P5, an encouraging start.
Leclerc's benchmark time of 1m19.426s remained unchallenged for the better part of the session until Sainz finally bettered the Monegasque by 0.164s with 20 minutes to go.
But a hot lap by Verstappen smashed the Ferrari drivers' best by 0.382 as the Red Bull delivered a warning shot. However, Leclerc overhauled Sainz to get within 0.159s of the championship leader.
Sainz would have none of it however and the Spaniard pressed on to put a 1m18.750s on the board that outpaced Verstappen by 0.130s.
A late but productive charge by Norris pushed the McLaren driver up to fourth, but Sainz concluded first practice at the top of the timesheet, with Verstappen and Leclerc following behind.
Behind the top four, Russell led Perez, Hamilton and Ricciardo while the Alpine pair of Esteban Ocon and Alonso rounded off the top ten.
Vettel topped the second half of the field from Lance Stroll, while AlphaTauri's FP1 let Gasly and Tsunoda lower than they wished, which was also the case for Alfa's Zhou Guanyu who edged Williams' Alex Albon for P15.
Magnussen's lowly P17 – just ahead of Schumacher – wasn't the step forward result Haas was hoping to receive from its updated car, but the day is young and gaining comparative data with the older-spec sister car was the team's main task in FP1.
Bringing up the rear at the end of FP1 were Kubica and Latifi.
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