Lewis Hamilton knows it is crucial he follows up his perfect Friday with another pole position ahead of the Spanish Grand Prix given Barcelona's qualifying history.

Hamilton is not prone to hyperbole following practice on Friday, but even he could not contain himself after destroying the field over the two sessions at the Circuit de Catalunya, remarking it was "a great day".

The currently dominant 29-year-old, aiming for a fourth consecutive victory, finished half a second quicker than Mercedes team-mate Nico Rosberg come the conclusion.

Hamilton is now a red-hot favourite to make it four poles in five races this year, and for another win that would finally see him overhaul Rosberg in the championship standings.

That victory, though, relies on qualifying more at this race than many others as in 23 past grands prix at the circuit the winner has started from top spot on the grid on 17 occasions, including 11 of the last 13.

"It's very difficult to overtake here," said Hamilton.

"Even following backmarkers in practice it was very difficult to get past, so position is everything.

"With the pace we have, it is always important to have pole position, and I'll do everything I can to get myself as high as possible for the race."

For now, Hamilton could not be happier with his performance and that of the car, with Mercedes' nearest rivals being Daniel Ricciardo in his Red Bull and Ferrari's Fernando Alonso, albeit almost a second and 1.5secs adrift respectively.

"It's going really well," added Hamilton. "We're getting back into it after a long break, so to get back into the car and feel that positive step forward...

"I'm sure I'll go back and analyse some things, find where I can improve because there are always places to do that.

"But Friday was a smooth day. I've not had a Friday like that for a long time."

Whereas Hamilton is riding the crest of a wave at the moment, four-times champion Sebastian Vettel suffered another low.

Vettel had most of Friday off as his Red Bull incurred a wiring loom fault after four laps of the first session which then sidelined him for all of the second, putting him on the back foot for the rest of the weekend.

Behind the leading quartet, McLaren's Jenson Button, second quickest on the hard compound tyre in the morning session, dropped to seventh fastest on the quicker medium rubber, a staggering 2.3secs behind Hamilton.

As for Marussia's Max Chilton, on a run of 23 consecutive finishes, his second session was a troubled one in which he was plagued by engine trouble before beaching his car in the gravel late on to finish 19th and 5.6secs down.