Lewis Hamilton admitted he struggled on the opening day of running at the F1 Saudi Arabian Grand Prix as he ended the day almost a second off the pace.

Hamilton was only 11th fastest in Free Practice 2, more than half a second off the pace set by team-mate George Russell and 0.996s away from Max Verstappen’s session-topping time.

It followed Free Practice 1 in which the Mercedes driver was sixth best, though 1.17s away from the pace.

“I definitely struggled in the session. I’ve struggled in both sessions,” the seven-time world champion admitted.

Across the garage, Russell was running some development parts which were not on Hamilton’s car.

“I’m not really sure what those are, just been focusing on my run programme,” he admitted.

“Of course, if there’s things being tested on the other car we’ll know about it once we’ve had the debrief.”

Russell also looking for answers

Though Russell fared better on the timesheets, he held a similar view to his team-mate following Friday’s two practice sessions.

“Not sure what power modes everyone was running and that’s always something in practice sessions,” Russell began.

“For sure Red Bull are out front but we’re going through and learning lots of things that will help in the short-term, medium term, and just need to pick up things overnight to see what we can do for this weekend.

“I think you just can go out there, maximise the package you’ve got try and get the set-up in the sweet spot,” he added.

“We’re not going to find a second overnight, as much as I’d love to do that.

“We need to just continue to understand and recognise: is the sort of new direction we’re taking as a team the correct one?

“That’s for the guys and girls back in the factory [and] everybody here to unpick the data.

“For me, this weekend, and the small group of engineers, you just go out there and try and maximise that.”

Mercedes has a final hour of practice to tune its car tomorrow, starting at 16:30 local time (00:30 AEDT Sunday).