Christian Horner insists Red Bull will not be giving up their Formula One world titles without a fight after witnessing Mercedes grind them into Bahrain's desert sand.

For the second successive week Lewis Hamilton spearheaded a Mercedes one-two, and although he and Nico Rosberg were thoroughly dominant, F1 put on a riveting show under the lights of the Bahrain International Circuit.

The gap to their rivals, however, was eye-watering as third-placed Sergio Perez finished 23 seconds adrift of Rosberg, yet that would have been at least a minute but for a safety car from lap 41 that bunched up the field.

As for four-times champions Red Bull, Daniel Ricciardo was a highly impressive fourth after starting from 13th, with Sebastian Vettel in sixth after the reigning champion complained of issues with straight-line speed.

After four years of domination of their own, Red Bull find themselves having to play catch up to Mercedes in terms of technical innovation as the German manufacturing giant has undoubtedly got to grips with the new regulations for this season far better than their rivals.

Assessing Red Bull's new role as hunter rather than being the hunted, team principal Horner said: "It is not an insignificant gap we have to close to the Mercs, and our focus is just on closing that.

"We started 2012 not in great shape given the change in regulations with the blown diffuser, we were on the backfoot, but we fought our way back into the championship.

"We'll do our very best to do that again this year. The important thing is not to allow too much of a distance to grow in the first third of the year.

"The problem is, and it's no secret, we are significantly down on straight-line performance than Mercedes.

"For the first time we saw their true pace where they obviously went for it, and they're not hanging about.

"The guys at Renault (who supply Red Bull's power unit) know that and are working on it, and anything we can do to close that gap will only get us closer to them.

"We just have to keep working at it, nobody is giving up. We know where we need to improve and we'll keep pushing."

Compared to Red Bull's testing performances in Bahrain a few weeks previously when it appeared they would be unable to finish a race in the first few weeks, the Milton Keynes-based team has made considerable strides in such a short period.

Horner added: "To achieve what we have been achieving has been seriously impressive."