Sebastian Vettel sputters to stop in 1st practice in Spain, Lewis Hamilton records top time

Red Bull driver Sebastian Vettel of Germany looks around as his car is taken away after he lost control during a first free practice session at the Barcelona Catalunya racetrack in Montmelo, near Barcelona, Spain, Friday, May 9, 2014. The Formula One race will be held on Sunday. (AP Photo/Manu Fernandez) (The Associated Press)

Red Bull driver Sebastian Vettel of Germany helps to put his car on a truck after he lost control during a first free practice session at the Barcelona Catalunya racetrack in Montmelo, near Barcelona, Spain, Friday, May 9, 2014. The Formula One race will be held on Sunday. (AP Photo/Manu Fernandez) (The Associated Press)

MONTMELO, Spain – Sebastian Vettel hit another obstacle in his already troubled Formula One title defense when his Red Bull sputtered to a stop early in the Spanish Grand Prix's first practice session on Friday.

Lewis Hamilton steered his Mercedes to the fastest lap time of 1 minute, 27.023 seconds, while 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 4.6-kilometer (2.9-mile) Circuito de Barcelona-Catalunya when an electrical problem caused his Red Bull to stop.

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 back of his malfunctioning car.