David Coulthard column: Ferrari must improve or risk losing Alonso

Sebastian Vettel has taken a lot of impressive grand prix victories in his time and the one in Germany on Sunday was right up there among them.

It was a win that owed a lot to track position, which he earned by qualifying second to Lewis Hamilton's Mercedes and making a good start.

There's no question that, had one of the Lotus cars got past him, Vettel would have found it difficult to win. But he controlled the race extremely well and fully deserved it.

People forget it because of the amount of success he has had, but a lot of Vettel's victories have been by small margins, although not many by as small as on Sunday.

He tends to manage his races, pushing the car only as far as he needs to do. This was a bit different. He was managing the race, certainly, but the pressure he was under was greater than it usually is.

The first time Red Bull would have known for sure that Vettel was going to win that race was when he exited the last corner. It was that close.

You could see in his eyes after the race how much it meant to Vettel, and how much he had enjoyed the close, tough battle.

I continue to be impressed by Vettel, and that's not because I have a historical relationship with him through Red Bull Racing. I continue to be impressed by Fernando Alonso, too, for example.

Vettel is doing a fantastic job this year and if he carries on like this it's hard to see how anyone will prevent him winning a fourth world title.

This is a tough time for Lewis Hamilton. It's very hard for us as broadcasters to explain why Mercedes are the kings of qualifying but just can't seem to get it together in the race, with one or two exceptions.

The team themselves admit they don't understand it - so there's no way we can say what's going on.

Hamilton was obviously frustrated after the race, and it's good that he doesn't hide it. He clearly doesn't like the way these tyres work, and he's not afraid to say it.

It doesn't make things easy for his PR handlers, but it's right that he is open and honest about his feelings on that subject.

It was very clear from the start of the race that Hamilton was in trouble - he only just managed to hold off the two Lotus cars in the first few laps and it was no surprise when Kimi Raikkonen and Romain Grosjean emerged as Vettel's main contenders for victory.

The hotter it is, the better it seems to be for Lotus, and Grosjean finally produced the race weekend he desperately needed to.

I have been critical of him in the past, and rightly so, but we have always known the speed is there. His problem has been harnessing it on a consistent basis and not bouncing off things.

Grosjean seemed to have himself more under control in Germany, and yet the speed was there, too. It's combining those things he has struggled with so often.

There was an illuminating moment in the interview we did with him on the BBC after qualifying. Suzi Perry asked him how he was going to get it together to have a strong weekend and he said it was just a question of believing in himself.

It sounded like the sort of thing a psychologist would say, but the way Grosjean said it meant it sounded like it was from the heart, rather than just like he had been told to say it.

Maybe that's the key for him - sourcing that self-belief. If he can keep driving like he did in Germany, his day will come.

It was Grosjean who was Vettel's main challenger for much of the race.

He got ahead of Raikkonen thanks to an impressively long first stint on the fragile 'soft' tyre, and it was only the team's decision to throw the dice with Raikkonen at the end of the race, running him on a short final stint on the 'soft' tyres, that meant Grosjean lost second place.

It was a tough decision for him to be told to make way for Raikkonen so the Finn could have a go at overtaking Vettel, but everyone understands why it was made.

For one thing, Raikkonen has earned that right through the consistency of his performances in their season and nine races of being team-mates; for another, in terms of the championship, it was the only decision that made sense.

It gave Raikkonen three more valuable championship points, and the way Vettel is going at the moment, Raikkonen needs every single one he can get.

Despite finishing second with Alonso fourth, Raikkonen remains third in the championship behind the Spaniard.

We don't immediately think of Lotus as title contenders, because that team has had some poor seasons since Alonso won his last title for them in 2006, when they were called Renault.

The Ferrari name is bigger than Lotus, but actually Lotus are in a better position at the moment to challenge Vettel than Ferrari are.

You get the impression Ferrari believed more in their title chances last year, when they were in a worse competitive position, than they do this season.

That's almost certainly because last year they were ahead on points and now they're behind.

It's not a case of shoulders down at Ferrari, but everyone in F1 recognises how difficult it is to close a gap, especially when you are fighting against a superior car.

Alonso is normally so positive about his chances, but his post-race comments were revealing. He said: "They need to do something and they need to do it now." That's as close to banging the table as you get.

It's a long time since Alonso won a world championship and that's not because he's not putting in world championship-level performances. He does that all the time.

If this continues for that much longer, you have to wonder how much longer Alonso can stay at Ferrari.

He is 32 this year. He has still has five or so years left at the very top level, perhaps a bit more, but if Ferrari cannot get it together soon he is going to have think about his future there.

David Coulthard was talking to BBC Sport's Andrew Benson