Carlos Sainz emerged quickest from a three-way Hungarian Grand Prix first practice battle with Red Bull's Max Verstappen and Ferrari team-mate Charles Leclerc.
Sainz had the final say of an intriguing session, posting the fastest time of one minute 18.750secs to finish 0.130s clear of F1 champion Verstappen, with Leclerc a further 0.159s adrift.
For the opening 25 minutes of the hour-long outing at the Hungaroring, Verstappen and the Ferrari duo dominated, often separated by just thousandths of a second before Leclerc managed to pull away by a quarter of a second to the Dutch driver.
At the midway point, Mercedes entered the fray, albeit with the W13 encountering a degree of bottoming, as opposed to the violent porpoising and bouncing the car has previously suffered from this season.
George Russell managed to slot himself in between Leclerc and Verstappen, 0.180s behind the Monégasque, while Lewis Hamilton was fifth at that point, just under three-tenths of a second adrift.
With 19 minutes remaining, Sainz then posted the quickest lap with a 1:19.262s but his advantage lasted all of two minutes as Verstappen shattered the time by almost four-tenths.
In a clear battle of wills, however, between the Spanish driver and Verstappen, Sainz improved further by 0.130s to claim the advantage ahead of late running on the harder compounds of tyres.
McLaren's Lando Norris managed to emerge as best of the rest behind the lead trio, just over half-a-second back ahead of Russell, who finished a further three-tenths down.
As for Sergio Perez, who has become lost for the most part since Red Bull updated its car after his Monaco Grand Prix triumph, the Mexican finished sixth quickest, 0.872s off the pace.
There was an unusual moment for Perez midway through the session as he suffered a sneezing fit as he was driving, letting out three sneezes in rapid succession, which led to him apologising for allergies.
Hamilton had to settle for seventh, almost a full second down.
McLaren's Daniel Ricciardo, along with Alpine pair Esteban Ocon and Fernando Alonso completed the top 10, with the latter duo around 1.5s back.
Aston Martin's Sebastian Vettel and Lance Stroll, with their cars sporting a new rear wing that has drawn considerable attention, were 11th and 12th on the timesheet, both 1.6s down.
Further down the order, Kevin Magnussen and Mick Schumacher were 17th and 18th for Haas, with the former in a VF-22 carrying a heavy upgrade, notably to the floor and sidepods.
Come the conclusion to the session, just a tenth of a second separated the pair.
Hungarian Grand Prix first practice results
1. Carlos Sainz [Ferrari] 1:18.750s
2. Max Verstappen [Red Bull] +0.130s
3. Charles Leclerc [Ferrari] +0.289s
4. Lando Norris [McLaren] +0.549s
5. George Russell [Mercedes] +0.856s
6. Sergio Perez [Red Bull] +0.872s
7. Lewis Hamilton [Mercedes] +0.960s
8. Daniel Ricciardo [McLaren] +1.091s
9. Esteban Ocon [Alpine] +1.598s
10. Fernando Alonso [Alpine] +1.627s
11. Sebastian Vettel [Aston Martin] +1.633s
12. Lance Stroll [Aston Martin] +1.664s
13. Pierre Gasly [AlphaTauri] +1.706s
14. Yuki Tsuonda [AlphaTauri] +1.945s
15. Guanyu Zhou [Alfa Romeo] +2.060s
16. Alex Albon [Williams] +2.084s
17. Kevin Magnussen [Haas] +2.171s
18. Mick Schumacher [Haas] +2.277s
19. Robert Kubica [Alfa Romeo] +2.429s
20. Nicholas Latifi [Williams] +2.663s
5. Sergio Perez [Red Bull] +1.021s
6. George Russell [Mercedes] +1.104s
7. Fernando Alonso [Alpine] +1.233s
8. Alex Albon [Williams] +1.286s
9. Lando Norris [McLaren] +1.397s
10. Yuki Tsunoda [AlphaTauri] +1.479s
11. Daniel Ricciardo [McLaren] +1.516s
12. Nicholas Latifi [Williams] +1.569s
13. Pierre Gasly [AlphaTauri] +1.597s
14. Valtteri Bottas [Alfa Romeo] +1.600s
15 Zhou Guanyu [Alfa Romeo] +1.639s
16. Kevin Magnussen [Haas] +1.759s
17. Esteban Ocon [Alpine] +1.850s
18. Lance Stroll [Aston Martin] +1.905s
19. Mick Schumacher [Haas] +1.950s
20. Sebastian Vettel [Aston Martin] +2.264s