Analysis: Rivals humbled by Mercedes pace in Spain. Horner writes 2015 season off

The good news for Mercedes' rivals is that the team won the Spanish Grand Prix by a margin 4 seconds smaller than last year.

The bad news is that margin was 45 seconds after 66 laps, an average of 0.68s per lap. Last year it was Red Bull who trailed in third, 49 seconds adrift, with Ferrari over 90 seconds off the winning Mercedes.

Ferrari has halved that deficit 12 months on, while Red Bull has slipped back further, finishing the race a lap down on the winner. This has led the team boss to claim that for Red Bull, 2015 is already a "write-off".

In fastest race lap terms, Ferrari was 1.6 seconds off Mercedes' best in the race and Red Bull 2.85 seconds off. Williams was 2.1 seconds behind and a minute off the Mercedes in overall race time.

"It is not enjoyable being in a Grand Prix like today when you are just going around, you're not racing," Red Bull team boss Christian Horner said after the race. "We want to get back. The frustration is that not all of it is in our hands. We are relying on our partner (Renault).

His fellow director Helmut Marko confirmed to BBC that if they do not have a competitive engine soon, then either Audi takes over the team or they will leave F1.

"This year is pretty much of a write-off, you have just got to go for it, even if you end up using 20 engines. It is far easier to make a fast engine reliable than a reliable car fast.

"We want it as soon as possible but Renault are nervous about reliability, so I think it will still be the second half of the year before we see anything significant."

"It is a positive that we got four engines to the finish - that is a step forward from previous races. Reliability has taken a step forward, so focus desperately needs to turn to performance."

Renault is understood to have a significant performance step lined up for the next engine, due in Monaco, while other manufacturers, including Mercedes, are believed to have an updated engine, using up some development 'tokens' due for imminent release.

There were increasing suggestions from informed sources this weekend that Red Bull boss Dietrich Mateschitz's recent comments about potentially pulling out of the sport are not 'hot air', but that he means it. Meanwhile there were also strong suggestions from a number of quarters this weekend that Renault is lining up to go ahead with its own team, possibly taking over the Lotus operation from Genii, which is understood to be low on cash flow at present.

Toro Rosso boss Franz Tost had confirmed earlier in the season that he would welcome being bought out by Renault, but attention seems to be focussing on Enstone, where Renault used to be the proprietors.

As for Ferrari, the team has had a strong start to the season with a podium in every race, four for Vettel and one for Raikkonen, but here despite bringing an update kit understood to comprise 16 components, they were 8/10ths of a second off the Mercedes in qualifying and 45 seconds behind at the flag.

To be fair to them, Vettel's strategy was compromised slightly by countering Lewis Hamilton's attempted undercut at the first stop, but it would only add up to a few seconds difference from an optimised strategy.

Vettel said that the picture is skewed and the gap looks bigger than it probably is due to the conditions of Spain. He is right: At half distance, when both men were on Medium tyres, Rosberg was just 10 seconds ahead of Vettel, but once they got onto the Hard tyres, the Mercedes pulled away dramatically, from 16 seconds on Lap 46 to 45 seconds at the finish on Lap 66.

"Obviously, if you look at the gap in the race it was the biggest gap we’ve had so far so your conclusion might be that it’s not so good, but I think we’re quite confident that we’re going in the right direction," said Vettel. "For some reason, I don’t think we were so competitive here which explains the gap. Now we’re obviously trying to understand and find the reasons. Either this track didn’t suit us or the conditions really suited Mercedes. I think it’s more likely to be one of the two, because if you take the average, obviously we’ve been closer in the last couple of races."

Operationally Ferrari also struggled a bit this weekend, with problems getting the new package validated on both cars, which led to Raikkonen using the old one for qualifying and the race. He also had a set of tyres damaged in tyre blankets, the kind of thing that happens when a team is on the limit.

Last year Spain showed the largest margin of the season for Mercedes, the reality is that for the average tracks, the gap is smaller. But it will have been a useful learning for Mercedes and particularly for Hamilton, who has yet to sign his Mercedes contract for 2016 onwards.

If he was considering making a play to move to Ferrari next season, he will have seen that the team he is with at the moment still has very much the upper hand.