Jarno Trulli won the first Grand Prix of his career as Michael Schumacher's unbeaten start to the season ended in an incident-packed race in Monaco.
MONACO GRAND PRIX
1 J Trulli (Renault)
2 J Button (BAR)
3 R Barrichello (Ferrari)
4 J Montoya (Williams)
5 F Massa (Sauber)
6 C Da Matta (Toyota)
7 N Heidfeld (Jordan)
8 O Panis (Toyota)
The Renault driver held off BAR's Jenson Button in a close finish, with Rubens Barrichello third for Ferrari.
Schumacher's hopes of a sixth straight win were dashed when he was hit by Juan Pablo Montoya after Fernando Alonso's crash had brought out the safety car.
McLaren's David Coulthard was forced out of the race in an earlier crash.
Montoya recovered from his scrape with Schumacher to finish fourth for Williams, ahead of Sauber's Felipe Massa.
Toyota's Cristiano Da Matta was sixth, Nick Heidfeld scored Jordan's first points of the season and Olivier Panis was eighth in the other Toyota.
Minardi's Zsolt Baumgartner was the only other driver to finish the race.
Kimi Raikkonen's retirement on lap 28 continued McLaren's miserable start to the season, and Ralf Schumacher's Williams stopped seven laps from the end.
Trulli made the most of his first pole position to lead from the start, with team-mate Alonso overtaking Button and Michael Schumacher slipping back to seventh.
But there was immediate drama on lap three when the engine of Takuma Sato's BAR failed, throwing up a wall of smoke.
As the cars slowed down, Giancarlo Fisichella's Sauber ploughed into the back of Coulthard's McLaren and flipped over.
Both drivers were forced out of the race, and the safety car made its first appearance.
Michael Schumacher manoevred his Ferrari nicely back into contention after the first round of pitstops, leapfrogging Button and Raikkonen by lap 26.
But the complexion of the race altered dramatically with two controversial incidents in the space of five laps.
First Alonso came spinning out of the tunnel on lap 42 after crashing as he tried to lap Ralf Schumacher's Williams.
Alonso's demise left team-mate Trulli to fight Michael Schumacher alone.
But the world champion's challenge ended when he was struck from behind by Montoya as the pair followed the safety car.
Schumacher appeared to lock his brakes and Montoya could not react in time to avoid him, shunting the Ferrari into the wall.
It took the pressure off Trulli, although he was relieved to see the chequered flag as Button closed to within just 0.4 seconds by the finish.