Valtteri Bottas believes the upgrade the Mercedes Formula 1 team has bought to Suzuka should represent a "decent step" as it seeks to catch Ferrari in the Japanese Grand Prix.
Mercedes enjoyed a dominant run of form from the start of the season, but has struggled to match the pace of the Ferrari since the F1 summer break.
The team has brought a small sidepod aero upgrade to the car for this weekend and Bottas is confident that it will improve the performance of the Mercedes in the final part of the season.
"We have a pretty solid update package this weekend. Obviously getting a tryout tomorrow, but in theory yes, it should give us more performance," said Bottas.
"How much [it works] is something we'll find out.
"We have some rough numbers about it, but should be a decent step, in terms of upgrade packages so far.
"It's been a pretty good car this year, but it is again a track with a mixture of different things.
"There are some decent straights where we definitely have a disadvantage compared to Ferrari, so they're going to be gaining time to us there.
"But there's some good sections full of corners, which we know we are good in, and hopefully with the upgrade package will be even better.
"We've already in the second half had tracks that we thought they should be quite good for us, and they've been able to beat us.
"For sure, if they perform better than us here, it means we need to work harder if we're going to be beating them next year."
Mercedes took its first win since the summer break last time out at the Russian Grand Prix, with Hamilton and Bottas scoring a one-two finish after benefiting from the team orders controversy at Ferrari.
When asked if the volatile situation between Sebastian Vettel and Charles Leclerc at Ferrari could help Mercedes regain its advantage, Hamilton said: "No, because I don't think we need help. That's not the way I look at things.
"We want them to be at their best so we can challenge them at their best and ultimately if we beat them it just makes it better.
"There's been a lot of noise made after the last race. But I saw Seb after the race and he looked like he was in a harmonious place.
"They are a formidable force, they are doing an incredible job at the moment and they are going to be very hard to beat in these remaining races and they've clicked this package.
"It's interesting to see how that evolves into next year's car.
"So I think hopefully we'll have an even closer season next year. These next five races will be interesting to see how that relationship evolves."