Nico Rosberg made fastest lap time in opening practice at Spa for Belgian GP, two-tenths clear of team-mate Lewis Hamilton.
Red Bull ace Daniel Ricciardo took third fastest for Red Bull ahead of Ferrari’s Kimi Raikkonen.
Sebastian Vettel set fourth fastest ahead Red Bull’s Daniil Kvyat and the local hero Max Verstappen.
The session was interrupted with red flags when Pastor Maldanado crashed into a barrier but he emerged unhurt despite smashing the front of his car.
McLaren have endured a miserable season so far and with Fernando Alonso and Jenson Button finishing 16th and 18th respectively, there is little indication they will improve this weekend.
A second practice session is scheduled for 1200 GMT before third practice and qualifying Saturday ahead of Sunday’s race.
Hamilton, searching for a third world title, leads the standings on 202 points, with Rosberg on 181 and Vettel on 160.
Sky Sports F1’s Martin Brundle was optimistic by the early pace of top title rivals Ferrari and Red Bull:
“Nice to see Red Bull and Ferrari in there with competiitve times.” Martin said. We don’t know what fuel they’re using, but it’s nice and competitive in that top 10.”