Top speeds at Spa are registered on the track's Kemmel Straight, which runs from the exit of Eau Rouge to the Les Combes corner.
Thanks to their low-drag aero configuration, and the grunt of their Mercedes engine, Force India's Esteban Ocon and Sergio Perez whizzed through the speedtrap at 318.4 and 317.6 km/h respectively, just beating Valtteri Bottas by a whisker.
Looking down the order, McLaren's Fernando Alonso clocked in tenth at 310.5 km/h, a top speed deficit which once again underlines the efficiency of his MCl32 chassis.
Stoffel Vandoorne, who was using Honda's new spec-3.6 engine, was strangely relegated down to P17 with a top velocity of just 303.5 km/h.
Sauber's underpowered pair of Marcus Ericsson and Pascal Wehrlein were the usual laggards.
Gallery: The beautiful wives and girlfriends of F1
Keep up to date with all the F1 news via Facebook and Twitter
Kimi Antonelli is one step away from F1 immortality. A commanding victory in Austin, a…
Max Verstappen left the United States Grand Prix with a podium finish but little satisfaction,…
Kimi Antonelli is ready to put the finishing touches to a remarkable Formula 1 breakthrough,…
George Russell cut a frustrated figure after a miserable United States Grand Prix, admitting his…
Kimi Antonelli inched closer to a historic F1 world title in Austin on Sunday with…
Full race results from the United States Grand Prix at the Circuit of the Americas,…