Valtteri Bottas seeks to double up in Barcelona after maiden F1 title at Russian Grand Prix

Catalonia: Valtteri Bottas seeks to prove his maiden Formula One success at Sochi was no fluke by repeating the feat for champions Mercedes in this weekend`s Spanish Grand Prix.

The unflappable Finn, who has emerged as a serious threat not only to his more celebrated team-mate Lewis Hamilton, but also Ferrari`s championship leader Sebastian Vettel, believes his determination, form and speed justify his optimism.

"Getting that win has definitely given me a lot of confidence that I can do it - because I always thought that I had the ability.

"And now it`s done all I want to do is to go and win again and again," said Bottas.

Another Bottas win would not be a surprise at a venue that has a habit of producing more different winners than anywhere else - if he is successful, he will be the 11th different winner in as many years.

The Circuit de Catalunya, a track drivers and teams know intimately from days of pre-season testing, is capable of throwing up the most unexpected and unpredictable results.

That was demonstrated last year by Dutch teenager Max Verstappen`s win on his debut for Red Bull.

Bottas` recent bright form - pole position in Bahrain and victory at Sochi - has confirmed him as a worthy successor to retired 2016 world champion Nico Rosberg at Mercedes where, temporarily, he has managed to put three-time world champion Hamilton in the shade.

But that does not mean much as the teams, all with upgraded packages, begin the European season with Ferrari likely to set the pace if the weather conditions put the onus on tyre management.

The Italian team has a car that is less demanding on its rubber and operates well across a wider range of temperatures than the Mercedes.

For Mercedes boss Toto Wolff, it is a concern, but not yet a serious worry.

"I don`t think there is a particular pattern yet," he said. "It is all very marginal with tyre compounds, interaction with the track, the surface of the track and the track temperature itself.

"But, one thing is for sure -- we have a very fast race car and a fast qualifying car. We just need to tune it and this is an exciting exercise."

Tyre suppliers Pirelli will take their harder tyres, not greatly loved by Mercedes on the evidence so far this year, to Barcelona this weekend.

"I think it will be close - in fact more than very close," added Wolff.

"Ferrari came out of the winter with a good car and it seems to suit Sebastian a lot. So, we just need to stretch ourselves to perform as good as we can and, if we do like we did in Russia with Valtteri, we are able to compete."

He said the team had no immediate explanation for Hamilton`s uninspired form in Sochi where he struggled with the car.

"Lewis had a difficult weekend in both qualifying and the race," said Wolff.

"We`ve since been unpicking what happened to understand why we couldn`t get the car in the right window so he could feel comfortable with it."

Hamilton said he was mystified by his lack of pace as he finished fourth to fall 13 points adrift of Vettel after four rounds of the championship.

"We must give him the tools he needs to do the job in the next races and that will be a big focus for us," added Wolff.

"Barcelona will be interesting as our pre-season was not spectacular in Spain. It`s a very different track to Sochi and we`ll be running with harder tyres. So, we are taking this season one race at a time..."

Ferrari and Mercedes may be the front-runners again, but Red Bull expect to be close in pursuit with a heavily-updated car while local hero Fernando Alonso has more modest hopes.

After failing to start in Russia, he is just hoping his revised McLaren will be on the grid to take part in his home race this Sunday.