Barcelona, Spain - Red Bull's decision to change Sebastian Vettel's car for the Spanish Grand Prix backfired on Friday when an electrical problem sidelined the quadruple Formula One world champion for most of practice. With race favourite Lewis Hamilton fastest in the morning session for dominant Mercedes, Vettel was forced to park up by the side of the track early on and with just four laps completed. Circuit de Catalunya marshals handed him a fire extinguisher as he inspected the car before hitching a ride back to the paddock on a scooter. "Due to an electrical problem that has damaged the wiring loom of Car No. 1, Sebastian will not be able to take part in FP2 (second practice)," Red Bull said before the afternoon session started. "The Team will use the time to fix it to be ready for FP3 (the final session before qualifying) tomorrow." Vettel, winner of the last nine races of 2013 and four championships in a row, has had a difficult start to the new V6 turbo era with Red Bull's engine partner Renault playing catch-up with Mercedes. The last time the German was in action at a Spanish circuit, testing at Jerez in January, he spent most of his time in the garage watching mechanics work on the car. Hamilton, winner of the last three races and closing in on championship-leading team mate Nico Rosberg, went from strength to strength with a fastest lap of one minute 27.023 seconds set six minutes from the end. That was 0.868 quicker than Jenson Button, who was best of the rest for McLaren, and the impressive margin on a sunny morning further underlined the Briton's status as the man to watch. Rosberg, who had said on Thursday he just needed a "normal weekend" to regain the momentum, suffered a cooling issue that cut short his session. He was fifth fastest. Vettel's Australian team mate Daniel Ricciardo, who has made an impressive start with the team, was third. Ferrari's Fernando Alonso, the local favourite for his home race after winning last year, had plenty of banners in the grandstand urging him on and ended up fourth on the timesheets. With the opening long-haul races in Asia and the Middle East out of the way, all teams have brought updates to their cars and Friday's practice sessions were being closely watched for any signs of change in the pecking order. In a bizarre early incident, a wing mirror on Sergio Perez's Force India broke off and was left flapping around on a wire. The Mexican completed the lap with it in his hand. Race favourite Lewis Hamilton set the pace for dominant Mercedes in first Spanish Grand Prix practice on Friday while the pain remained the same for Sebastian Vettel despite a Red Bull chassis switch.

Hamilton's fastest lap of 1m27.023, set six minutes from the end, was 0.868sec quicker than Jenson Button who was best of the rest for McLaren.

The impressive margin on a sunny morning at the Circuit de Catalunya further underlined the Briton's status as the man to watch after three consecutive wins.

Championship leader Nico Rosberg, who is four points clear of team mate Hamilton and says he just needs a “normal weekend” to regain the momentum, suffered a cooling issue that cut short his session. He was fifth fastest.

ELECTRICAL GREMLINS

Quadruple world champion Vettel, who had a miserable pre-season test in Spain and has had a difficult four Grands Prix since then, kicked off the first European race weekend of the year with another setback.

Vettel, winner of the final nine races of 2013, was using a different chassis to the one raced so far but he completed just four laps before pulling over with an electrical problem.

Marshals handed him a fire extinguisher as he inspected the car before hitching a ride back to the paddock on a scooter.

“We had a full electrical shutdown on Seb's car.”

Team principal Christian Horner said: “We're not sure what caused it. It cut the radio and everything.”

The car was trailered back to the pits but the problem prevented Vettel from taking any further part in the morning session.

His Australian team mate Daniel Ricciardo, who has outqualified Vettel in three of the four races and passed him in the past two after the German was instructed to let the faster car through, was third fastest.

LOCAL HERO

Ferrari's Fernando Alonso, the local favourite for his home race after winning in 2013, with plenty of banners in the grandstand urging him on, was fourth on the timesheets.

With the opening long-haul races in Asia and the Middle East out of the way, all teams have brought updates to their cars and Friday's practice sessions were being closely watched for any signs of change in the pecking order.

In a bizarre early incident, a wing mirror on Sergio Perez's Force India broke off and was left flapping around on a wire. The Mexican completed the lap with it in his hand.

RESULTS

1 Lewis Hamilton (Britain) Mercedes - 1min 27.023

2 Jenson Button (Britain) McLaren - 1:27.891

3 Daniel Ricciardo (Australia) Red Bull - 1:27.973

4 Fernando Alonso (Spain) Ferrari - 1:28.128

5 Nico Rosberg (Germany) Mercedes - 1:28.168

6 Kimi Raikkonen (Finland) Ferrari - 1:28.337

7 Kevin Magnussen (Denmark) McLaren - 1:28.423

8 Pastor Maldonado (Venezuela) Lotus - 1:28.744

9 Sergio Perez (Mexico) Force India - 1:28.779

10 Felipe Massa (Brazil) Williams - 1:28.791

11 Daniil Kvyat (Russia) Toro Rosso - 1:28.792

12 Nico Hulkenberg (Germany) Force India - 1:28.828

13 Jean-Eric Vergne (France) Toro Rosso - 1:28.859

15 Adrian Sutil (Germany) Sauber - 1:29.688

16 Jules Bianchi (France) Marussia - 1:29.820

17 Romain Grosjean (France) Lotus - 1:29.944

18. Giedo van der Garde (Netherlands) Sauber - 1:30.440

19 Max Chilton (Britain) Marussia - 1:30.748

20 Sebastian Vettel (Germany) Red Bull - 1:30.942

21 Kamui Kobayashi (Japan) Caterham - 1:30.997

22 Marcus Ericsson (Sweden) Caterham - 1:31.421