Sebastian Vettel is simply quicker than Mark Webber - Coulthard

Part of the job I have these days is to say what I see. In that role, I have been very critical of Romain Grosjean's early grand prix career - it was patchy and erratic, and he got involved in too many incidents.

That continued from last year into the beginning of this. But what a turnaround from that to his impressive performance in finishing third in the Japanese Grand Prix on Sunday.

Grosjean has clearly gone away, done some soul-searching and had great support from the Lotus team. That's unsurprising in the sense that they are part of the group that manages him. All the same, all credit to them for seeing his potential.

He has won races in the lower formulae and it's always better - and much easier - to try to make a quick driver consistent than a consistent driver quick.

I did a track walk with Grosjean on Thursday ahead of Japan and, when I brought up last season, he very quickly closed the subject down.

It's obviously part of what he has been working on. The mantras of whatever help he has had are obviously 'focus on the now' and 'influence the future'. And that's exactly what he did.

He out-qualified team-mate Kimi Raikkonen, who is no slouch, for the third race in a row and the fifth time in the last six races - and he made great use of his start to lead on the first lap and looked very solid at the front of the grand prix until the Red Bulls inevitably got past him later in the race.

If that had been Raikkonen leading and ultimately finishing third, people would have been waxing lyrical about what a great performance it was, so it's only fair we give Grosjean the credit that's due.

That sort of performance is what is expected of him and any world-class driver, and 27-year-old Grosjean seems to have stepped up his game.

He can't be criticised for losing out to the Red Bulls in the end. He did everything he could in defending from Sebastian Vettel and Mark Webber. It was a great performance.

The next step is to do that every weekend, which is what the great drivers who have gone on to win world championships are able to do.

The Red Bull strategy question

There was a lot of speculation after the race about whether Red Bull deliberately put Webber on a three-stop strategy to get him out of Vettel's way.

Do I think that Red Bull would deliberately compromise Mark's strategy to allow Sebastian to win? No, I don't.

At the point the strategy was being made, Vettel was still behind Grosjean, so there was no guarantee he could win.

I don't think on lap 11 - when Webber was called for his first stop - the team could make a decision with any certainty that Vettel would be able to catch and pass Grosjean.

Equally, Mark and the team were very clear before the race that they were all racing. And given Mark is leaving F1 at the end of the year, if he had something he believed to be factually the case, I suspect he would have said so publicly.

Why would he hide anything with four races of his F1 career to go if that was the case?

I don't think he would be holding back if he had anything to say, and if anything, given the strained relationship he has had with Red Bull adviser Helmut Marko, it would almost be a parting gift.

The facts are simple. The Pirelli tyre era in F1, since 2011, has shown that Vettel more than any other driver has been able to work with the peculiarities of the tyres.

The question marks over the strategy are a nice news story for those who want to stir the pot, but Mark is on the floor. He has done four re-matches with Sebastian in the same car and each time he has come up short.

It's a bit like when I was at McLaren. I don't believe I was ever given a lesser opportunity machinery-wise than Mika Hakkinen, but it was difficult for me to acknowledge until we weren't team-mates any more that he was simply quicker.

As much as I sat there with team boss Ron Dennis saying, 'you're giving Mika a psychological advantage', which he would deny, it was what it was.

Of course, there were times when I was disadvantaged. One example was Monaco 1996, and it lost me the win to Olivier Panis.

It was a damp race, I was leading Mika and the team brought Mika in for dry-weather slicks the lap before me, and that was the critical moment when I got passed.

But they would probably say now that they brought Mika in to see if it was safe for me to go on to slicks, and once we found out it was safe, I was brought in a lap later.

You can always argue it any way you want to suit the defence, but Mark is a bit heavier and sometimes hasn't been able to get the weight distribution just so. Seb just makes the tyres last longer. Those are the facts.

Management problems at Mercedes

On BBC F1 we try to have a hot-line to one of the teams on the pit wall each live race weekend. In Japan, it was to Mercedes and their team principal Ross Brawn.

It became very obvious from some of Brawn's responses to questions about whether he will stay there next year that there is some general unhappiness about the management structure at that team right now.

In January, Mercedes hired Paddy Lowe from McLaren to run the technical and sporting aspects of the team. The initial idea was for him to replace Brawn; then they decided to hold off on that and discuss how the structure would work during this season.

Obviously, Lowe is effectively the long-term replacement for Brawn, but the big question is what happens in the short and medium term.

Ross is the master at calming turbulent waters. He is the ultimate poker player and it's very hard to tell even when he's angry.

So for him to be discussing this publicly means he clearly thinks there is an issue. He thinks Mercedes are management-heavy and wants to understand exactly what role they are offering him, and that it excites him.

That suggests a conversation has either taken place or it has been suggested that there will be a change of role for him, because if they'd said he would be doing exactly the same role, he would not have a problem.

If anyone can defuse that situation, it's Niki Lauda, the team's non-executive chairman, who is a straight-talking guy.

And defuse it is exactly what he is going to have to do.

What I don't understand is why they are saying it will be sorted out at the end of the season. It's spilling out now, which means now is when it needs to be addressed.

David Coulthard was talking to BBC Sport's Andrew Benson.