Marc Marquez narrowly edged out Jorge Lorenzo and Dani Pedrosa in the opening MotoGP practice session at Brno.
Although Marquez's Honda was in front for most of the morning session in the Czech Republic, Lorenzo did pop his Yamaha ahead for a spell with a 1m56.840s.
Even when Marquez did return to the front, it was by only 0.037 seconds over Lorenzo, while Pedrosa was just 0.015s behind the Yamaha on the second Honda.
Aleix Espargaro put the Forward Yamaha fourth, ahead of Valentino Rossi on the other factory version and Stefan Bradl's LCR Honda.
Andrea Dovizioso was top Ducati in seventh, though Pramac's Yonny Hernandez made good use of a lap on Rossi's tail to slip in 0.021s behind the Italian in eighth.
Tech 3 duo Pol Espargaro and Bradley Smith completed the top 10.
Ducati is back up to five bikes this weekend with test rider Michele Pirro making his latest appearance on a third works entry. He was 11th.
Alex de Angelis began his MotoGP return in place of Colin Edwards on the second Forward bike with 19th place.
Pos Rider Bike Time Gap Laps 1. Marc Marquez Honda 1m56.803s 17 2. Jorge Lorenzo Yamaha 1m56.840s +0.037s 15 3. Dani Pedrosa Honda 1m56.855s +0.052s 17 4. Aleix Espargaro Forward Yamaha 1m57.002s +0.199s 15 5. Valentino Rossi Yamaha 1m57.065s +0.262s 18 6. Stefan Bradl LCR Honda 1m57.084s +0.281s 18 7. Andrea Dovizioso Ducati 1m57.169s +0.366s 15 8. Yonny Hernandez Pramac Ducati 1m57.190s +0.387s 17 9. Pol Espargaro Tech 3 Yamaha 1m57.634s +0.831s 18 10. Bradley Smith Tech 3 Yamaha 1m57.816s +1.013s 16 11. Michele Pirro Ducati 1m58.040s +1.237s 14 12. Andrea Iannone Pramac Ducati 1m58.061s +1.258s 14 13. Scott Redding Gresini Honda 1m58.301s +1.498s 15 14. Cal Crutchlow Ducati 1m58.340s +1.537s 16 15. Alvaro Bautista Gresini Honda 1m58.698s +1.895s 16 16. Hector Barbera Avintia FTR-Kawasaki 1m58.714s +1.911s 14 17. Hiroshi Aoyama Aspar Honda 1m58.895s +2.092s 18 18. Karel Abraham Cardion Honda 1m59.216s +2.413s 15 19. Alex de Angelis Forward Yamaha 1m59.959s +3.156s 18 20. Mike di Meglio Avintia FTR-Kawasaki 2m00.240s +3.437s 13 21. Michael Laverty PBM-Aprilia 2m00.345s +3.542s 16 22. Leon Camier Aspar Honda 2m00.445s +3.642s 16 23. Danilo Petrucci Ioda Aprilia 2m00.497s +3.694s 14 24. Broc Parkes PBM-Aprilia 2m00.752s +3.949s 16