Sam Bird and Richie Stanaway were quickest in Friday's free practice sessions at Spa.
The Mercedes reserve driver was fastest in the afternoon session, which halted towards its conclusion following an accident by Alexander Rossi bringing out the red flag, while Stanaway was quickest in the early running.
Bird heads into this weekend topping the standings after his victory in Monaco and gave an enlightening view on the contrasts of the two circuits.
Bird said: “Winning in Monaco was something I'd wanted to do. I did it and I hope I'll do it again, but now I have to forget about that and focus completely on the rest of the season. Driving this weekend is the perfect way to do that.
“Monaco is a rather slow, narrow circuit, where you're often in second gear. Spa is a different world altogether, with fast bends and long straights. We'll need a different car, particularly in terms of aerodynamic set-up.”
For Stanaway, it is an opportunity to kickstart his championship after an underwhelming opening to the campaign.
The New Zealander said: “It's better to start the weekend like this rather than against the barrier, like at Monaco!
“It's a circuit that I like a lot, and it's a completely different feeling to know from the outset where the turns are. We started working with little aerodynamic load.
“We then added a bit and the car became very quick. I really want some big results here.”
Another driving still searching for a big result is Carlin's Kevin Magnussen, who like Stanaway is keen to make an impression in FR3.5.
He was 3rd and 5th respectively on Friday.
He said: “Like everyone else, we did a lot of work on our set-ups between sessions and, unsurprisingly, we improved our times.
“You really can't make the slightest mistake with such small gaps. Personally, I made a small mistake during my best lap and it no doubt cost me first place.
“To get pole position you have to get a perfect lap, which is far from simple here.”
Afternoon times: Pos Driver Team Time Gap 1. Sam Bird ISR 1m58.838s 2. Richie Stanaway Lotus 1m58.869s + 0.031s 3. Kevin Magnussen Carlin 1m58.878s + 0.040s 4. Marco Sorensen Lotus 1m58.895s + 0.057s 5. Kevin Korjus Tech 1 1m58.901s + 0.063s 6. Daniil Move P1 1m59.068s + 0.230s 7. Nico Muller Draco 1m59.071s + 0.233s 8. Robin Frijns Fortec 1m59.113s + 0.275s 9. Arthur Pic DAMS 1m59.174s + 0.336s 10. Mikhail Aleshin RFR 1m59.286s + 0.448s 11. Carlos Huertas Fortec 1m59.384s + 0.546s 12. Walter Grubmuller P1 1m59.409s + 0.571s 13. Will Stevens Carlin 1m59.585s + 0.747s 14. Nick Yelloly Comtec 1m59.595s + 0.757s 15. Jake Rosenzweig ISR 1m59.623s + 0.785s 16. Jules Bianchi Tech 1 1m59.626s + 0.788s 17. Lucas Foresti DAMS 2m00.173s + 1.335s 18. Alexander Rossi Arden 2m00.377s + 1.539s 19. Andre Negrao Draco 2m00.619s + 1.781s 20. Giovanni Venturini BVM Target 2m00.738s + 1.900s 21. Zoel Amberg Pons 2m00.812s + 1.974s 22. Lewis Williamson Arden 2m00.975s + 2.137s 23. Yann Cunha Pons 2m01.091s + 2.253s 24. Vittorio Ghirelli Comtec 2m01.120s + 2.282s 25. Anton Nebylitskiy RFR 2m01.385s + 2.547s 26. Nikolay Martsenko BVM Target 2m01.528s + 2.690s Morning times: Pos Driver Team Time Gap 1. Richie Stanaway Lotus 1m59.441s 2. Alexander Rossi Arden 1m59.769s + 0.328s 3. Sam Bird ISR 1m59.877s + 0.436s 4. Nico Muller Draco 1m59.949s + 0.508s 5. Kevin Magnussen Carlin 1m59.985s + 0.544s 6. Kevin Korjus Tech 1 1m59.995s + 0.554s 7. Carlos Huertas Fortec 2m00.024s + 0.583s 8. Arthur Pic DAMS 2m00.050s + 0.609s 9. Daniil Move P1 2m00.188s + 0.747s 10. Jules Bianchi Tech 1 2m00.369s + 0.928s 11. Robin Frijns Fortec 2m00.377s + 0.936s 12. Anton Nebylitskiy RFR 2m00.492s + 1.051s 13. Nick Yelloly Comtec 2m00.510s + 1.069s 14. Marco Sorensen Lotus 2m00.578s + 1.137s 15. Jake Rosenzweig ISR 2m00.698s + 1.257s 16. Walter Grubmuller P1 2m00.722s + 1.281s 17. Vittorio Ghirelli Comtec 2m00.992s + 1.551s 18. Will Stevens Carlin 2m01.143s + 1.702s 19. Zoel Amberg Pons 2m01.267s + 1.826s 20. Andre Negrao Draco 2m01.287s + 1.846s 21. Mikhail Aleshin RFR 2m01.320s + 1.879s 22. Giovanni Venturini BVM Target 2m01.385s + 1.944s 23. Lewis Williamson Arden 2m01.428s + 1.987s 24. Yann Cunha Pons 2m01.618s + 2.177s 25. Nikolay Martsenko BVM Target 2m02.086s + 2.645s 26. Lucas Foresti DAMS 2m08.678s + 9.237s