Mercedes motorsport boss Toto Wolff has conceded to being a worried man in the wake of Sebastian Vettel's Malaysian Grand Prix victory.
Suggestions of another season of Mercedes domination in the wake of a comfortable one-two in the season-opening race in Australia were blown apart by Ferrari and Vettel in Malaysia.
As Vettel himself noted, his triumph was achieved "fair and square" as he beat reigning champion Lewis Hamilton by 8.5 seconds, with team-mate Nico Rosberg a further four seconds adrift in third.
Despite searing heat of more than 30 degrees, Vettel's Ferrari was kinder on its tyres, stopping just twice compared to three for both Hamilton and Rosberg.
It has left Wolff concerned, as he said: "We were pretty sure the three-stop strategy would work for us.
"We probably went a bit too aggressive on set-up, which pushed us into a direction of a three-stop.
"But in the circumstances, with the high temperatures, they were able to go at a faster pace over long runs than us.
"We need to analyse why that was the case, and it clearly shows it's not going to be an easy one.
"It is clear they won the race, which is worrying. It wouldn't be right to say we lost it."
Wolff at least gave credit where it is due to Ferrari, although has also admitted to surprise at how quickly his team have been reeled in given their margin of victory in Australia.
"Ferrari deserved to win," Wolff added.
"From a racing perspective, you have to acknowledge they have done a great development over the winter.
"For Formula One it (their win) is a positive, particularly after all the talk we had in Melbourne of a boring race and Mercedes running away with the championship.
"It is what Formula One needed, but we didn't expect them to catch us this quickly.
"We were pretty dominant in Melbourne - we were a little bit sceptical about our own advantage.
"That we've been caught up by a Ferrari in two weeks, that they beat us fair and square on the track, is a bit of a surprise, but equally a bit of a wake up call, which is good for us.
"We just need to analyse in the next couple of days where we went wrong, what we need to improve, whether we need to bring any developments forward and put them on the car quicker.
"Definitely we need to increase the pace of our development."
Wolff insists, though, Mercedes will not over-react to the situation, particularly as the cooler conditions at the next race in China in a fortnight are expected to favour his cars.
"There is no panic, but we are in a new situation," he said.
"We were not in control of things. We had new information which was different to what we had assessed over the weekend.
"Things didn't pan out in the way we expected them to pan out, but it was clear the winning streak would not go on forever."
Suggested to Wolff the loss was the end of an era, he said: "We must not be extreme in our assessment.
"In Melbourne there was extreme thinking we would win all season, and here we are two weeks later and we say is this the end of an era?
"It is not the end of an era - maybe the start of a new era, of a good battle, a battle we would like to take on.
"It's about staying calm, assessing, trying to return with confidence and with the speed we have had in the last couple of races."
Source: PA-WIRE
