F1: Martin Brundle worried about Mercedes' poor performance at Japanese Grand Prix

Brundle expressed deep concern over the team's ongoing struggle to address its car's issues, labeling it as "very worrying."

Last weekend's race at Suzuka saw Mercedes deliver one of its poorest performances in recent memory. 

George Russell managed only a seventh-place finish, while Lewis Hamilton trailed even further behind in ninth, marking a stark contrast to the team's usual dominance.

This lacklustre performance is part of a larger trend for Mercedes this season, particularly for Hamilton, who is yet to secure a podium finish, let alone a race win, a feat he last achieved in Saudi Arabia back in 2021.

To compound matters, Mercedes' decision to pursue a one-stop strategy at Suzuka following a red flag on the opening lap backfired due to excessive tyre degradation, further highlighting the team's struggles.

"They've got to understand this car and I think that's a grave concern for all of the people there," Brundle said on the Sky Sports F1 Podcast.

"There's a lot of very clever people, with a huge amount of resource, performance tools and budget. I'm not going to try and second guess what's wrong with it, or state what I think is wrong with it, because if they don't know, then I certainly don't know.

"They cannot get a handle on these ground-effect cars. This is the third season of these regulations. They turn up, they think they have aced it, a lot of positive noises, and then it still bounces a little bit with the porpoising.

"But their problem is, from time to time, the thing performs beautifully and they are really quite fast in phases. But, they can't seem to reproduce that session to session, let alone day to day, let alone Grand Prix to Grand Prix.

"This is the problem they have got - this knife edge of a car that sometimes looks like they have finally sorted it and more of the time they just can't understand it.

"When you've got that, when all of your tools and all your clever people don't correlate with the stopwatch and the performance of other cars on the track, and you can't seem to nail it down, then that's really frustrating and I would say very worrying."