The Renault driver beat Toyota's Jarno Trulli and McLaren's Kimi Raikkonen as Ferrari's gamble on an early debut for their 20005 car failed to pay off.

Michael Schumacher challenged Alonso in the early stages but retired with hydraulic failure after just 11 laps.

BAR's Jenson Button retired at his final pit stop while David Coulthard took eighth on the last lap.

Button stalled the BAR while in eighth place and although the team finally managed to get the car restarted, he pulled off at the end of the pit lane for his third consecutive retirement.

BAR beat Renault to second place in the world championship last season, but their fortunes this season have been dramatically different - Renault have now won all of the first three races.

It had appeared in Bahrain that they would face genuine opposition for the first time after Schumacher qualified second in the new Ferrari and pressed Alonso hard in the early laps.

But the German ran wide at Turn Nine on lap 11 as the Ferrari's electro-hydraulic systems began to falter and Schumacher pulled into the pits at the end of the lap.

Trulli kept Alonso in sight until the first pit stops, but the Renault eased clear thereafter to take a comfortable win.

"It was the hottest race I've ever been in, but the car ws extremely strong, especially after the second pit stop," Alonso said.

"Michael was close and I think that he was quicker than me in the first part of the race. But it is difficult to pass and I was not worried even if he did pass me because I knew our strongest part of the race would be at the end."

Trulli's second place confirmed Toyota's emergence as a major force.

The Italian, runner-up to Fernando Alonso for the second consecutive race, said: "The car was quick and reliable with no issues whatsoever.

"I realised midway through the race that it was futile to try to catch Fernando and we were safely in second.

"But we still have one place ahead of us, so we must keep pushing with that as the target."

Behind the two leaders, McLaren finally delivered on some of the potential that has been obvious in their car from the start of the season.

Raikkonen started ninth after another disappointing showing in qualifying, but both his car and that of team-mate Pedro de la Rosa were impressively fast in the race.

Raikkonen moved up to seventh after the start, was fourth after the first pit stops and then passed Mark Webber's Williams when the Australian spun at Turn Nine on lap 34, losing a place to Ralf Schumacher's Toyota as well.

Webber faced a determined assault from the charging De la Rosa in the final laps, and lost fifth place to the Spaniard into Turn Four with three laps to go.

De la Rosa looked rusty in his first race for more than two years as he stood in for the injured Juan Pablo Montoya.

But he was extremely fast in between numerous off-course excursions as he fought back from dropping down to 11th place on the first lap.

Behind them, Felipe Massa passed Rubens Barrichello's Ferrari, which was nursing a gearbox problem, for seventh in the closing laps.

Barrichello lost another place to Coulthard right at the end of the race.