McLaren's Jenson Button quickest in opening day's practice for Spanish Grand Prix

Jenson Button raised McLaren morale by leading the way in second practice for the Spanish Grand Prix.

Three weeks ago the team departed Bahrain feeling dejected after being deposed from the top of the drivers' and constructors' championships following a bitterly disappointing race.

Button was forced to retire a lap from home through mechanical failure, while team-mate Lewis Hamilton was only eighth due to issues at the first two of his three pit stops.

Button yesterday also bemoaned his lack of understanding so far this season at how to adequately switch on the Pirelli tyres.

The 32-year-old heads into Sunday's race trailing championship leader and reigning champion Sebastian Vettel by 10 points, with Hamilton four points down.

But in finishing with a lap of one minute 23.399secs around Barcelona's Circuit de Catalunya at the end of FP2, there is cause for some optimism, even if Friday times can often prove misleading.

Vettel was a close second, 0.164secs adrift in his Red Bull, followed by Mercedes' Nico Rosberg and then Hamilton, the latter half a second off the pace of his fellow Briton.

The Lotus duo of Kimi Raikkonen and Romain Grosjean finished hot on Hamilton's heels, the trio separated by just 0.055secs.

Red Bull's Mark Webber, who was involved in the only incident of note across the three hours of practice today when he trundled off at turn four, spraying gravel across the track on his return, was down in seventh, 0.666secs adrift of Button.

Seven-time champion Michael Schumacher of Mercedes, Sauber's Kamui Kobayashi and the Force India of Nico Hulkenberg completed the top 10, the latter just within a second of Button.

Ferrari duo Felipe Massa and Fernando Alonso were down in 11th and 14th respectively, the latter having topped the timesheet in FP1, albeit understood to be on a relatively low-fuel run.

Button ultimately improved on that time by over a second, however, seemingly as Ferrari concentrated on long-run pace in FP2.

For this weekend the Ferraris carry a raft of updates designed to hopefully propel them firmly into contention for the title.

Sporting a new exhaust concept and rear bodywork, the belief is if it works at this circuit, it will prove reliable for the rest of the European campaign at least.

Paul di Resta, who made way for Force India reserve Jules Bianchi in FP1, finished 1.289secs down in 15th.

After sitting out first practice for reserve Dani Clos, Narain Karthikeyan suffered a truncated second session, managing just two installation laps and without setting a time before his HRT ground to a halt.

PA