MANAMA (Reuters) -- Kimi Raikkonen relived past nightmares on Friday when an electrical problem halted his McLaren on the first day of practice for the Formula One season-opener in Bahrain.

The 2005 championship runner-up, dogged by engine failure in the past, slowed at turn four of the desert Sakhir circuit during the afternoon's second hour-long session.

The Finn helped marshals push the stricken car off the track before getting a ride back to the paddock on a motorcycle.

Raikkonen had been the fastest race driver in a soporific first session, with Renault's 24-year-old world champion Fernando Alonso and other race favorites making only fleeting appearances.

BMW Sauber's Polish reserve driver, Robert Kubica, was quickest in the morning on his first appearance at a grand prix weekend.

The afternoon was busier. All 22 drivers lapped and Briton Anthony Davidson, Honda's test driver, was quickest with a time of 1:31.353 despite gearbox problems.

Ferrari's Michael Schumacher emerged as the day's fastest race driver, 0.398 seconds off Davidson's pace in a boost for the seven times champion after a dismal 2005 season. "I think that compared to the other teams, we are looking competitive," said the German. "What is clear however is that Renault seem to be very quick straight out of the box which gives them an edge." Good day

Alonso, the youngest champion in Formula One history, did no timed laps in the morning but was fifth quickest in the afternoon.

"We had a good first day," said the Spaniard, taking to the track with the number one on his Renault for the first time. "The car feels like it did in winter testing. It is comfortable to drive and consistent."

However Alonso was less than two tenths quicker than Italian Vitantonio Liuzzi, whose Toro Rosso car with a restricted V10 engine was a surprising and controversial sixth in a field of V8-powered rivals.

"I'd say my good time was down to the fact that we did four days testing here last month," said Liuzzi.

Italian Jarno Trulli, in a Toyota, parked up during the afternoon session due to an electronics problem.

With a new three-part qualifying format forcing drivers to do more mileage on Saturday, while engines must still last for two successive races, the big names had no incentive to spend much time on track.

Sunday's race in Bahrain and steamy Malaysia the following weekend are two of the hottest and most demanding on engines.

"The new format of the weekend has seen teams take a variety of different approaches to their Friday running but, as we expected, the running was quite limited overall," said Renault engineering director Pat Symonds. "I am not sure we have yet seen the true state of play between the teams."

Japan's Super Aguri, the new 11th team, made a first appearance with Takuma Sato and Yuji Ide.

Ide, whose only Formula One experience before arriving in Bahrain amounted to 44 laps of the Barcelona circuit in a car derived from a four-year-old Arrows chassis, was slowest.