Russell explains root of torrid Azerbaijan start

George Russell says he needs to "step up" his "game" in Baku after a subdued and interrupted start to his Azerbaijan Grand Prix weekend.

The Mercedes driver was, by his own admission, off the pace of Lewis Hamilton during Friday's practice sessions, with his FP2 running severely disrupted by a power unit change between sessions - due to an issue detected in FP1 - and a late sensor failure.

Having finished the first practice hour eighth fastest, the 26-year-old could only achieve ninth-quickest in the final session of the day.

When asked by F1TV how the car felt during his time on circuit and if he could tell something was not right with his W15, Russell replied: "The problem was the engine in FP1. Then at the end [of FP2] it was actually a sensor failure, so we pitted because we thought we had a water leak, but we didn't.

"It was feeling okay, it wasn't feeling superb for me out there. I was struggling, I was definitely off the pace compared to Lewis [Hamilton].

"I was really struggling with confidence in the car and getting the tyres in the right window, so I need to try and step up my game and try and close that gap."

Mercedes is 'capable of something strong' in Baku

Hamilton, meanwhile, had a much more productive day, something Russell is taking solace in ahead of FP3 and qualifying.

His Mercedes team-mate finished second and third respectively in the two sessions, highlighting the underlying pace in the W15, which has been equipped with a previous-spec floor, around the streets of Baku.

However, the British driver is wary of the threat posed by the other top teams, singling out Ferrari, who topped FP2 courtesy of Charles Leclerc.

"It wasn't our finest Friday, that's for sure. Lewis is looking really quick out there, so we know the car is capable of something strong," said Russell.

"But once again, Ferrari look really, really strong around here - they always seem to be fast in Baku."