Montmelo: Sebastian Vettel hit another obstacle in his already troubled Formula One title defence when his Red Bull sputtered to a stop early in the Spanish Grand Prix’s first practice session on Friday.

Red Bull said an electrical problem that “damaged the wiring” of Vettel’s car meant he would not return for the afternoon practice session. That leaves Vettel with only one session to prepare on Saturday before qualifying.

After Vettel was whisked back to the paddock on the back of a scooter, Lewis Hamilton steered his Mercedes to the fastest lap time of 1 minute, 27.023 seconds. The British driver is looking to add to his three poles positions and hat-trick of wins after four races this season.

Hamilton’s teammate and F1 leader Nico Rosberg was limited to only nine laps due to a cooling issue.

Vettel was running through his fifth lap on the sunny and dry 4.6-kilometre Circuito de Barcelona-Catalunya when his Red Bull came to a halt.

Vettel helped push his RB10 out of the path of his rivals before a group of fans gathered at the fence to take photographs of the four-time world champion using a fire extinguisher on the rear of his malfunctioning car.

Red Bull had given Vettel’s car an older chassis in a move that the German called a “sanity check” to try and find an elusive answer to his car’s lack of pace.

The Austrian team renowned for its design had a bigger problem than speed, however, when Vettel was left stranded just after the fifth turn.

Hamilton hasn’t lost a step after a three-week break and showed that the other teams have yet to make headway despite their upgrades for the start of the season’s run of European events.

Hamilton bettered Jenson Button’s benchmark time with two late flying laps. His McLaren rival finished with the second best time.

Pablo Maldonado of Lotus recorded the most laps of the hour-and-a-half session with 34.

The session to prepare for Sunday’s race featured some close calls.

Sergio Perez had to box when the left mirror on his Force India car became detached and the Mexican driver had to grab it and drive one-handed while coming in.

Sauber test driver Giedo Van der Garde survived a bigger scare when he told his team he had “a break failure” and ran off course, barely missing the wall.

Hamilton trails Rosberg by four points despite having won the last three races in front of his teammate. The pair have won all four races and taken all four pole positions this year.

Vettel is having his worst session at Red Bull with only one podium finish so far and sits in a distant fifth place in the standings. He has even had to let new teammate Daniel Ricciardo pass him twice during the last two races.