BARCELONA, Spain, April 27, 2008 (AFP) - Defending drivers world champion Kimi Raikkonen extended his lead in this year´s title race to nine points on Sunday when he drove to a comfortable victory in an incident-filled Spanish Grand Prix.

The Finn, driving a Ferrari, led from start to finish, bar the pit stops, to dominate the contest and consolidate his and his team´s position as the in-form outfit after four races this season.

Raikkonen´s win was his 17th in a career often beset by bad luck in earlier times and endorsed the wideheld feeling that he has happier at Ferrari and in the form of his life.

His Ferrari team-mate Brazilian Felipe Massa drove a solid race to finish second, after starting third on the grid, ahead of Briton Lewis Hamilton in a McLaren-Mercedes.

But Hamilton´s team-mate Finn Heikki Kovalainen produced the day´s most spectacular and worrying moment when his car suffered a front-left puncture at 240 kph.

He lost control and flew off the track into a tyre barrier.

It took five minutes to pull his car clear and lift him out on to a stretcher, but he was later declared to be uninjured and stable after being taken to the medical centre - though he was flown to a local hospital as a precautionary measure.

Poland´s Robert Kubica continued his fine form by finishing fourth for BMW Sauber ahead of Australian Mark Webber in a Red Bull and Briton Jenson Button in a Honda.

Japanese Kazuki Nakajima finished seventh for Williams and Italian Jarno Trulli ninth for Toyota.

The race saw the Safety Car sent out twice following accidents.

Home hero Fernando Alonso of Spain was forced to retire in his Renault after blowing the engine. He started an unexpected second on the grid, but failed to match that in front of a crowd of more than 115,000 spectators at the Circuit de Catalunya.

Raikkonen made a fast, clean start to take the lead from his 15th pole position and first this year.

Behind him, his Ferrari team-mate Massa went left and wide to pass Alonso on the outside as they swept towards the first corner.

The big sun-bathed crowd of 115,000 spectators crowded into the Circuit de Catlunya gasped in disappointment, but there was nothing that Spain´s double world champion could do to prevent the Brazilian passing him with sheer speed.

Hamilton, starting fifth, took advantage of the cars swerving in front of him to spear down the inside of Kubica and, after almost running off the circuit, to squeeze ahead of him on the inside of turn one.

For both men, their aggression paid off as on this tortuously predictable circuit, where overtaking during the race is so notoriously difficult, it secured them good positions.

On the same lap, the opening one, however, there was drama when German Adrian Sutil spun and then hit his compatriot Sebastian Vettel, the Force India car smacking the Toro Rosso with enough force to wreck both of their races.

This brought out the Safety Car for two laps before Raikkonen began his charge again, opening up a clear 2.7 seconds lead by lap 10 ahead of Massa as the two Ferraris ran away at the front.

Alonso, Hamilton and Kubica filled positions three to five with Kovalainen sixth in the second McLaren.

Another accident on lap eight ended the hopes of both Nelson Piquet and Sebastien Bourdais, the Brazilian driving his Renault into the second Toro Rosso when he attempted an outrageously ambitious passing move down the inside. The Frenchman retired with a shrug and soon afterwards was joined by Briton Anthony Davidson who abandoned the race in his Super Aguri car. For the cash-starved Honda-supported team, it was a minor catastrophe in a season of worry - they do not know if they will survive for more than another week.

Piquet´s car was left abandoned out on the track at turn 10.

Alonso was the first man to pit, followed swiftly by the two Ferraris and Hamilton, but as the order was shuffled during the stops, Kovalainen speared off the track at turn nine, ramming his Renault heavily into the tyre-barrier. The front of his car was buried deep in the tyres and the Finn, in the cockpit, was out of sight seemingly in serious danger of bad injury.

But after several minutes his car was finally extracted and after he was lifted on to a stretcher he was well enough to signal with a ´thumb´s up´ that he was well and apparently unhurt.

Slow-motion replays from the cockpit footage showed that his car went out of control when his left front wheel blew up at 230 kph. It looked like a straightforward tyre failure.

On resumption, Raikkonen was left to build his lead again as the two Ferraris led the field. Hamilton was third, Kubica fourth and Alonso, after the stops, fifth. It did not last long.

As Raikkonen completed his 35th lap, Alonso pulled to a halt, his engine spewing out blue smoke.

The Renault power unit had failed dramatically. His fans in the big crowd gave him generous applause and he responded as he walked back to the pits.

Nico Rosberg, of Germany, then retired in similar, if more dramatic fashion, when his Williams car´s Toyota engine blew up as he parked by the pit wall on the main straight.

This left only 13 of the 22 starters still running.

Massa was first to make a second pit-stop as Raikkonen set another fastest lap and pulled further clear before pitting himself ahead of Hamilton and Kubica.

This left Raikkonen ahead by two seconds, as they headed to the chequered flag with Hamilton closing the gap on Massa to just nine-tenths of a second as they crossed the line.