Ricciardo says Red Bull within half a second of Mercedes

The Australian was cautious when questioned on Red Bull's pace relative to the reigning champion outfit, claiming the gap is less than 0.5s, but is unsure of the exact margin of Mercedes's advantage.

"From testing, it looked like less than half a second," said Ricciardo. "I am not sure how much less. But less than half a second."

He also downplayed any reliability concerns with the Renault power unit that may have come out of the winter, saying that the testing programme was the best he's experienced since joining the Milton Keynes squad in 2014 - and that the speed trap data suggests the engine is strong.

"I had a few hiccups during testing but it was nothing dramatic I would say," added Ricciardo.

"So I think looking at the last few years, at least while I have been with the team, winter testing has never been flawless for us. I think this year was probably the best one up until my time with the team.

"We know things can turnaround. The 2014 race here was pretty…. forget the result, even the reliability was pretty impressive considering what we had done in testing.

"It is not a concern for me. Throughout the season maybe things will happen, you have to be prepared for that, but we are coming here pretty confident – I would say with that.

"I think our speed traps looked pretty good in Barcelona. We know we will not be as quick in a straight line but we are closer than where we were last year. We will see when everyone has it turned up this weekend."

Verstappen: We need to improve

Max Verstappen shared Ricciardo's view that the Red Bull probably isn't quite ready to challenge early pacesetters Mercedes and Ferrari, claiming that the team 'needs to improve' when the season kicks into gear.

"There were definitely some positives to take with us [from testing]," he said.

"For sure we need to improve, but I think everyone wants that all the time, especially with the new regulations this year. There is still a lot of opportunity to improve the car. We arrive here, for sure it is a step forward again, but if it is good enough I don't know.

"It is still early days. We have to wait and see. With these cars you can develop more than last year's car where you already had a few years before of developing around the same kind of philosophy.

"Sometimes maybe the start can be not as good but you can develop it very quickly and change it. I think the car is not bad but we can definitely improve."

Additional reporting by Jonathan Noble