Red Bull "can be very close" to Mercedes and Ferrari

Mercedes and Ferrari have shared the spoils on all three days of pre-season testing so far, while Red Bull drivers Ricciardo and Max Verstappen have more often than not found themselves a second or more adrift on the timing screens.

Ricciardo, however, has warned the RB13 has not yet done much in the way of performance testing and thus still had plenty of potential to close in on the two leading teams.

"I think for now we haven't really got too involved in the performance runs," he said on Wednesday.

"We're trying to get some laps, some consistent laps, for reliability as well, to make sure nothing's getting hot or there's no problems.

"The laptimes, for now it's still not too representative but I think we can expect Mercedes and Ferrari to be at the front. But I think we can be very close as well."

The Aussie also said Red Bull still had more pace to get from the Renault power unit.

"For now, this first test, we're pretty happy," he said of the French manufacturer's new engine. "We know there's a bit more to come, but hopefully next week we can start to push it a bit more and I think by the end of next week everyone will be seeing what they've got.

"I'm confident we can be again a bit closer than we were last year, and we'll see from there. Today's been globally positive."

Mercedes mileage advantage not a worry

Whereas Red Bull has run into a few reliability disruptions over the week so far, including an exhaust issue on Wednesday afternoon, reigning champion Mercedes has been maximising the mileage.

The Silver Arrows have cleared the 150-lap mark on all three days so far, with Ferrari maxing out at 139 laps with Vettel on Wednesday and Red Bull completing less than 100 laps on each occasion.

Ricciardo, however, suggested the mileage deficit compared to Mercedes was par for the course.

"It's been like this I guess since 2014. We were obviously working on that, but we don't expect to be doing 150 laps like Mercedes.

"I guess they expect to do it, because they've got that pretty good foundation and we're still experimenting with a lot of things. It would be nice to get a few more laps, but I think from what I learned on day one, I think today I learned a lot more.

"And I think even though we only did 20 more laps, maybe, than I did on day one, I think it was more useful and productive for us. If Max can get 80, 100 laps tomorrow, I think that will be a pretty good test for us."

Additional reporting by Erwin Jaeggi