Aleix Espargaro tops Silverstone practice
The Aprilia rider coped with the unseasonal chilly conditions best to lead the charge into Saturday qualifying.
The Spaniard's lap of 1min 58.183sec was nearly seven tenths clear of Jorge Martin, with South African Brad Binder's KTM placing third.
MotoGP's return after a mid-season break was going well for Marco Bezzecchi who was quickest in the morning session.
And he was on target to remain ahead of the pack until a bone-crunching fall with around five minutes left on the clock.
Catapulted into the air after losing control of his bike he walked gingerly back to the pits hoping he had done enough to make the top 10 and a direct pass to the main qualifying session.
Despite times tumbling Bezzecchi, racing for Valentino Rossi's VR46 Ducati-satellite team, held on to finish in seventh.
World champion Francesco Bagnaia struggled for pace on his factory Ducati in the morning but posted the sixth best time when it mattered.
He leads the riders standings by 35 points from Martin with Bezzecchi a further point back ahead of this ninth round of the 20-race season.
In a change of format the first session had no significance on Saturday's qualifying order, leaving riders and teams the chance to try out different bike and tyre set ups without consequence.
The top 10 from the second hour-long practice are joined as usual by the fastest two riders from Q1 to determine the first five rows of the grid both for Saturday's sprint race and Sunday's main event.
Among those relegated to Q1 were a trio of former world champions - Marc Marquez, Fabio Quartararo and Joan Mir.
The MotoGP grid welcomed back Pol Espargaro, the Spanish rider and Aleix's younger brother making his return after suffering serious injuries following a violent crash at the opening weekend in Portugal in March.