Big new Mercedes upgrade worth three tenths, Antonelli told
Mercedes has finally brought a major upgrade to Sepang and both Antonelli and Russell rate it a big step, though a possible engine upgrade for Austin is still undecided.
Max Verstappen topped opening practice at Sepang, but Mercedes believes its substantial new upgrade could yet transform the competitive picture this weekend.
Championship leader Kimi Antonelli said he had been told the long-awaited package is worth around three tenths.
"I've been told that it's three tenths, which is an important jump, but we must bear in mind that it's the result of work that has lasted months," he said.
George Russell, four tenths behind Red Bull's Verstappen early in Malaysia, agreed that the package represents a significant step, largely because Mercedes has brought almost nothing since May.
"It's a big step," he said.
"We consider it a big step simply because it's been so long since we last brought an upgrade."
Russell said the package principally adds downforce while attempting to preserve Mercedes' strong straight-line efficiency.
Auto Motor und Sport reports that Mercedes has substantially reshaped its sidepods and engine cover, with more pronounced ramps towards the floor and rear of the car, accompanied by underfloor changes.
"I hope it will put us back at the front on these tracks, which have been a bigger challenge for us in the last six races," Russell said.
Meanwhile, reports that Mercedes could introduce an ADUO engine upgrade - potentially involving the turbo - in Austin remain premature.
The team told Auto Motor und Sport that no decision has yet been made, with Mercedes instead waiting to see how the next grands prix develop.
Related: Will Antonelli bounce back at Sepang, as Schumacher expects?
