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.
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