Charles Leclerc called Mercedes' performance in the practice sessions at the Australian Grand Prix "very impressive", and believes they still have not shown their full strength.

Ahead of Sunday's Formula One season opener in Melbourne, Charles Leclerc topped first practice before Kimi Antonelli and George Russell climbed above him in the second session.

McLaren's Oscar Piastri led the way in second practice, though both Mercedes drivers were within 0.35 seconds of the home favourite in Australia.

Mercedes caught the eye of many during pre-season, with a few teams even accusing the Silver Arrows of not abiding by the new engine regulations.

Nevertheless, they showed some of their power in practice, and Leclerc expects to see more during Saturday's sessions.

"FP1 looked positive but then FP2 I think the teams are showing little by little a bit more and, unfortunately, we seem to be on the back foot especially compared to Mercedes, that seems to be very, very strong," said Leclerc in his post-session TV interview.

"I don't think that they showed everything in low fuel but on high fuel it was very impressive.

"It's the first time probably that we see how much there is to them and it's a bit more than what I would have liked, but it's the way it is.

"Then, on the other side, it's been quite a positive start to the weekend and we'll keep working very hard in order to try and maximise everything for tomorrow."

Russell has appeared in 152 races in F1 across his time with Mercedes and Williams though he has been unable to mount a title charge in that time.

The British driver accrued 319 points last year, which saw him win two races in Canada and Singapore as well as earning seven podiums, the most he has managed in his F1 career.