Lewis Hamilton's rivals will be out to defeat him in Spanish Grand Prix

Lewis Hamilton's rivals will be seeking to put the brakes on the seemingly unstoppable Mercedes driver's title defence, as Formula One returns to Europe for this weekend's Spanish Grand Prix in the outskirts of Barcelona.

The reigning world champion has won three of the opening four flyaway races to take a 27-point lead in the drivers' standings over teammate Nico Rosberg and Ferrari's Sebastian Vettel — a further point adrift in third. He is on course to become the only British racer since Sir Jackie Stewart to win three drivers' titles.

Rosberg, who took the title fight down to the wire last season, has been outdriven by his teammate in both qualification and the Grands Prix. But he has shown flashes of the brilliance he displayed last season in recent races, failing to beat Hamilton to pole just by the blink of an eye in China and driving a feisty race against the Ferraris in Bahrain.

The Ferrari Challenge

The Spanish Grand Prix often holds the potential for a shuffling of the pecking order as teams take advantage of the three-week break in the build-up to the race to introduce the first major upgrades of the season.

There is unlikely to be a major upheaval at the front of the field, but the spotlight will nevertheless be on the Mercedes vs Ferrari battle for any indications of whether the Maranello-based squad has made inroads into their German rival's advantage.

Home Hero

One man hoping for a significant improvement in performance this weekend will be home hero Fernando Alonso. His McLaren-Honda team have had a troubled start to the year. But he is hopeful the threeweek gap has given his squad enough time to find ways to move him up the field.

"We are seeing improvements race by race, and I want to ensure that we maintain this consistency throughout this weekend," said Alonso, who returns to the scene of his mysterious pre-season testing crash.

"It will be very difficult... but I'm hopeful that the start of the European season will be positive for us and allow us to carry momentum into the next few races."