Mercedes won't use softs tyres at all in first week of 2016 F1 test

It means Lewis Hamilton will have to wait to unleash the true potential of the F1 WO7 Hybrid with Mercedes going for reliability over performance over the opening four days at Barcelona.

Asked by Autosport about the grinding out of the laps and what he felt was the potential of the car, Hamilton replied: "It's a good question. With these tyres and the car being lighter, we still have to unlock it.

"The set-up requirements are different this year, and maybe also how you make these tyres last.

"I'm just waiting for the day when we have more tyres and use the super-soft and the ultra-soft, and start unleashing it and see how it goes.

"Those are the test days I actually prefer, when you can find out what the car is like, make some set-up changes. When you're pounding round, it's less exciting."

In splitting the driving duties for the day, Nico Rosberg completed 74 laps in the morning, with Hamilton adding 88 in the afternoon for a daily total of 162.

It means Mercedes has racked up 490 laps so far, and not one of them on any of the soft compound tyres.

It will be the same for Thursday, with Hamilton to run in the morning, and Rosberg taking over the wheel in the afternoon.

Mercedes' game plan has differed starkly to that of Ferrari, with Sebastian Vettel used the ultra-soft to set the fastest lap of the week so far on Tuesday.

Asked if he was surprised by Ferrari's tactic, Hamilton replied: "I'm not surprised and I didn't even know that was the case.

"We came with a target and we're sticking to that. Everyone else has their own plan that works for them.

"I've been really happy with the plan the team has implemented in the last couple of years. It's given us great results so we'll just stick with that."

Following his stint on Monday, Hamilton complained of a sore neck and back on Tuesday - resulting in Mercedes changing its driver line-up plans for the final two days.

After his half day in the car on Wednesday, Hamilton was feeling no ill effects as he said: "Today I feel great.

"It's like going to the gym when you've not been for ages and you do a hard workout, and the next day you feel a lot of pain.

"It doesn't matter how much you work your neck, and all the different exercises you do, when you get in the car it works in a different way. You can't simulate it in the gym.

"You have physio, it's a bit bruised up for a day, but today it's great."