It was yet another difficult day of running for Belgian rookie Stoffel Vandoorne in Friday's free practice in Sochi for this weekend's Russian Grand Prix.

The McLaren-Honda driver earned himself a 15-place grid penalty for Sunday's race after his car was fitted with its fifth MGU-K and turbo-charger of the season.

It will mean a tough afternoon for the Belgian, who will now need to start from the back row of the grid.

Despite this mishap, the team had a productive day evaluating a handful of new components and conducting some aerodynamic development work.

“We had some engine problems again in FP1 – and that means we get a 15-place grid penalty this weekend. Still, it was really only a matter of time before we got a penalty since the start of the season has been tough for us,” he said. “Unfortunately, today was a tough day but you have to try your best to move on from it.”

“There's nothing much we can do about the situation we're in at the moment. Still, let's hope some improvements will come soon. FP2 wasn't a 100 per cent problem-free session, but at least we were able to get some more laps under our belts. Hopefully tomorrow we'll have a smoother day.”