Max Verstappen comfortably led the way at the end of second practice for a Belgian Grand Prix in which he knows he faces a fight for points from the back of the grid.
Red Bull's reigning F1 champion finished 0.862secs clear of title rival Charles Leclerc after posting a lap of one minute 45.507s, which was also just over a second faster than the best time from FP1 from the latter's Ferrari team-mate Carlos Sainz.
Sainz had to settle for fifth on the timesheet, a tenth slower than his benchmark FP1, with McLaren's Lando Norris and Aston Martin's Lance Stroll.
If this had been the qualifying session, Stroll would be on pole as Verstappen, Leclerc and Norris have all been hit with power unit penalties and will start at the back of the grid, with their positions determined by their one-lap performances on Saturday.
Lewis Hamilton, who along with Mercedes team-mate George Russell has also taken on new power unit elements but without penalty, was fifth quickest, albeit 1.386s off the pace at the end of the soft-tyre runs.
Hamilton and Russell, however, have been seemingly presented with Mercedes' best opportunity for scoring its first win of the season, albeit with the likes of Sainz and Red Bull's Sergio Perez firmly in the mix.
Perez, however, was not a factor in either practice session, with the Mexican a lowly 10th at the end of FP2, a remarkable 1.839s behind team-mate Verstappen.
Sandwiching Hamilton and Perez were Alpine departee Fernando Alonso, Russell and another driver who will be leaving his current team at the end of the season in McLaren's Daniel Ricciardo.
The conditions were typical Spa - cool, grey, with showers looming, as occurred at the end of FP1 and threatened at the end of the second session.
Verstappen appeared the most comfortable around F1's longest track which offers numerous overtaking opportunities, leading to the prospect of a possible podium finish for the Dutch driver.
In the bottom half of the field, Williams' Alex Albon was the best of the rest, the first of the drivers just over seconds down.
Pierre Gasly, who sat out FP1 for Red Bull junior Liam Lawson, returned and in the AlphaTauri and was 14th fastest ahead of Aston Martin's Sebastian Vettel.
Alfa Romeo's Valtteri Bottas, who had endured another problematic FP1 as he missed the session bar two installation laps due to mechanical issues, was 18th, ahead of Williams' Nicholas Latifi and Haas driver Mick Schumacher.
Belgian Grand Prix second practice session results
1. Max Verstappen [Red Bull] 1:45.507s
2. Charles Leclerc [Ferrari] +0.862
3. Lando Norris [McLaren] +1.082
4. Lance Stroll [Aston Martin] +1.128
5. Carlos Sainz [Ferrari] +1.142
6. Lewis Hamilton [Mercedes] +1.386
7. Fernando Alonso [Alpine] +1.468
8. George Russell [Mercedes] +1.535
9. Daniel Ricciardo [McLaren] +1.748
10. Sergio Perez [Red Bull] +1.839
11. Alexander Albon [Williams] +2.013
12. Zhou Guanyu [Alfa Romeo] +2.110
13. Yuki Tsunoda [AlphaTauri] +2.151
14. Pierre Gasly [AlphaTauri] +2.275
15. Sebastian Vettel [Aston Martin] +2.360
16. Esteban Ocon [Alpine] +2.437
17. Kevin Magnussen [Haas] +2.701
18. Valtteri Bottas [Alfa Romeo] +2.912
19. Nicholas Latifi [Williams] +3.105
20. Mick Schumacher [Haas] +4.434