Red Bull F1 boss believes team is closing the gap to Mercedes

Lewis Hamilton and Nico Rosberg were in a class of their own at Barcelona, finishing almost 50 seconds clear of Red Bull's Daniel Ricciardo.

Red Bull boss Christian Horner thinks, however, that Mercedes' advantage last weekend was flattered by circumstance.

Ricciardo lost time early on stuck behind the Williams of Valtteri Bottas, while Sebastian Vettel had to battle through the field from 15th on the grid - having stopped in qualifying and lost further places on the grid thanks to a gearbox penalty.

"If you look at the last stint in particular, where Mercedes were pushing flat out and Sebastian and Daniel had a bit of clear air, we definitely have moved a bit closer," said Horner.

"It is a significant gap that we still have to overcome. But it is great to see we have made progress and made a step ahead of the Ferraris and the rest of the field.

"The 48-second gap is slightly artificial because we lost a lot of time behind the Williams in the first stint

"And once you find yourself in no-man's land until the end of the race you are then just managing the tyres."

Horner was also encouraged by the fact that Vettel appeared to be back on form, having struggled in the early stages of this season with the RB10.

"It was a great performance by Seb," he said. "He really went for it and he passed other drivers pretty much everywhere, apart from the conventional place at the end of the [start/finish] straight.

"He made the strategy work for him. He knew he had to make the passes and I thought it was a fantastic drive by him."