Mercedes motorsport boss Toto Wolff is predicting an "interesting" battle between his team and Ferrari at the Spanish Grand Prix.

As Formula 1's European season gets underway, all eyes will be on the upgrades each team brings, as the much-anticipated development battle at the front steps up a gear.

So far, it has been the Brackley-based team's inability to optimise the Pirelli tyres that has allowed the Scuderia to take advantage, with both squads taking two wins each in the first four races.

However, looking ahead to this weekend's race in Catalonia, Wolff admits to a little trepidation at just how the top two will compare.

"Barcelona will be interesting as our pre-season was not spectacular in Spain,” the Austrian admitted. “It's a very different track to Sochi and we'll be running with harder tyres.

“We are taking this season one race at a time. If we deliver the best possible work from Friday onwards, then we'll be ready to win and fight with Ferrari.”

On a broader note, the season now heads into a busy period, with seven races in 11 weeks, and Wolff acknowledged how important it is for Mercedes to try and cultivate an advantage over their rivals.

“The prevailing feeling is that there is lots of homework to do to come back stronger with a car that can perform on a consistent level every weekend,” he claimed. “I have the feeling that we are moving in the right direction but we need 24/7 shifts to achieve our ultimate targets."

On his drivers, Toto added: "We expected Valtteri to develop through every single race and step up his performance and he's shown that. He's coped extremely well with his calm approach to setbacks and he hasn't been carried away with success.

“It came early in Bahrain with the pole position and then he had a setback in the race. He replied with an exceptional performance in Sochi, in just his fourth Grand Prix for Mercedes, and showed that he's on the right path.

"On the flip side, Lewis had a difficult weekend in both qualifying and the race [in Sochi]. We have spent our time since then unpicking what happened to understand why we couldn't get the car in the right window so he could feel comfortable with it.

“There are no magic bullets to understanding that, just a lot of hard work and attention to detail. 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.”

Finally, Wolff also admitted he wasn't ruling out the third member of F1's 'big three' from making a recovery after a disappointing start to 2017.

“At the moment there are two top teams fighting for both championships and I expect Red Bull will also eventually join the club,” he said.

“The small margins we are seeing this season are demonstrated by the closeness at the top of the Drivers' championship and even more so by the one point advantage we have in the Constructors'. This fight will continue on to the end of the season and we will be prepared for that battle."