As the cars lined up for the start Olivier Panis has a problem and the start is aborted with the Toyota being sent to the back of the grid. The race is reduced to 77 laps. As the cars set off on the second parade lap Panis fails to get off the line and has top be pushed into the pit lane, from where he eventually joins the race.

* Lap 1: At the start Jarno Trulli and Fernando Alonso get away well and Alonso gets ahead of Jenson Button as they go into the first corner. Takuma Sato makes the best start and brushing past Michael Schumacher and Kimi Raikkonen emerges in fourth place. Raikkonen is fifth with Michael Schumacher sixth ahead of Rubens Barrichello, David Coulthard, Juan Pablo Montoya and Mark Webber. At the back Christian Klien tangles with Zsolt Baumgartner. Klien tries to keep going but understeers into the wall at the Grand Hotel Hairpin. At the end of the lap Trulli is 0.8s ahead of Alonso.

* Lap 3: The first three cars have pulled away from the field which is bottled up behind Sato. The Japanese driver has an engine problem and puffs of smoke appear from the rear of his car. As he goes into Tabac Corner, the engine blows. Sato pulls off to the inside as the others try to find a way through in the smoke. Montoya and Webber get through but Coulthard slows and is hit from behind by Giancarlo Fisichella. The Sauber flies over the rear of the McLaren and ends up upside-down. The Safety Car is sent out immediately. Fisichella emerges unscathed. Coulthard goes to the pits but the damage to the rear of the car is too much and he too is out. Ralf Schumacher, who is running in 13th place also pits.

* Lap 4: As the cars circulate behind the Safety Car, Jordan decides to bring in Nick Heidfeld in the hope of getting a strategic advantage. The German rejoins without loosing a place.

* Lap 8: The race restarts at the beginning of lap eight and Montoya scrambles past Barrichello at Ste Devote to move up to sixth place.

* Lap 10: At the front Trulli sets the fastest lap of the race while at the back of the field Ralf Schumacher is finally able to overtake Baumgartner for 15th place.

* Lap 12: Trulli sets a third consecutive fastest lap but his lead over Alonso is still only 1.2s. Eighth-placed Webber pulls off with a mechanical problem and at the back Ralf Schumacher gets ahead of Gianmaria Bruni to move up to 13th place.

* Lap 13: Montoya stops and falls back from sixth place to 10th. Giorgio Pantano, who is running 11th disappears with mechanical trouble.

* Lap 16: Trulli has pushed his lead out to 2.7secs while Alonso remains under pressure from Jenson Button. There is then a gap back to Raikkonen and Schumacher. Barrichello is sixth with Cristiano da Matta in seventh with Felipe Massa chasing him in the Sauber. In ninth place is Nick Heidfeld’s Jordan but he is under pressure from Montoya. The only other runners are Olivier Panis, Ralf Schumacher and the two Minardis. Bruni pits and drops behind Baumgartner.

* Lap 18: Button heads for the pits and falls back from third place to seventh.

* Lap 19: Raikkonen now pits and he rejoins still behind Button. The disappearance of the McLaren means that Michael Schumacher can speed up.

* Lap 20: Fourth-placed Barrichello goes into the pits for his first stop. Michael Schumacher sets the first of four consecutive fastest laps as he tries to make up lost ground.

* Lap 21: Seventh-placed Massa comes into the pits and falls back to 10th.

* Lap 23: Trulli increases his lead to 4.1secs while Alonso is still 4.4s ahead of Schumacher, despite the fact that Schumacher has done four fastest laps, bringing down the gap from 6.6s. Fourth-placed Da Matta pits and drops back to seventh.

* Lap 24: Trulli stops and Alonso goes into the lead with Schumacher second. Trulli rejoins third. Further back Panis pits for the first time.

* Lap 25: Alonso stops and so Michael Schumacher takes the lead. Alonso rejoins third ahead of Button.

* Lap 26: Schumacher pits but when he comes out he is still behind Trulli and Alonso. His fast laps mean that he is now ahead of both Raikkonen and Button. Barrichello is sixth with Da Matta seventh and Heidfeld in eighth.

* Lap 28: Raikkonen goes into the pits and retires with mechanical trouble.

* Lap 29: Montoya and Heidfeld have been fighting for seventh place, the two men going across the chicane on lap 28. In the Mirabeau corner Heidfeld makes a mistake and Montoya is able to get ahead at the Grand Hotel Hairpin.

* Lap 31: Heidfeld pits and falls back from eighth to 10th.

* Lap 32: Traffic has closed the gap between Trulli and Alonso but it is clear that Jarno is faster as he begins to build his lead again. Michael Schumacher is third with Button fourth, Barrichello fifth and da Matta sixth.

* Lap 37: Trulli has increased his lead again to 2.4s but the order is unchanged. Ninth-placed Ralf Schumacher pits and drops behind Heidfeld.

* Lap 42: Alonso tries to lap Ralf Schumacher in the tunnel but gets offline and crashes heavily. A Safety Car is sent out and Button, da Matta, Montoya, Massa and Heidfeld all go into the pits.

* Lap 43: Trulli stops and Michael Schumacher goes into the lead but behind the Safety Car. Immediately behind him on the road is Montoya.
 
* Lap 46: The field is getting ready to restart when Michael Schumacher slows in the tunnel. Montoya tries to avoid the Ferrari but the two cars seem to collide and Schumacher goes into the barriers. He drives to the pits and retires.

* Lap 47: Trulli begins to pull away again with Button behind him and Barrichello third but unable to keep up the same pace. Everyone else is a lap behind with Montoya fourth, da Matta fifth and Massa sixth and Heidfeld seventh. A further lap behind is Ralf Schumacher and Panis. The only other runner is Baumgartner.

* Lap 52: Da Matta is given a drive-through penalty for failing to observe blue flags and this drops him behind Massa.

* Lap 55: Barrichello pits but he remains in a solid third place but is now nearly 40 secs behind Button. Further back Panis also stops again but he stays ninth.

* Lap 70: The order is unchanged but Ralf Schumacher goes out with a mechanical problem, retiring from eighth place.

* Lap 74: Button has closed to within a second of Trulli but there is little chance he can overtake. Further back Massa is under great pressure from da Matta.

* Lap 77: Trulli wins his first victory with Button just 0.497s behind him. Barrichello is third. Montoya is a lap down but finishes fourth while Massa and da Matta cross the line side-by-side, the Sauber a tenth of a second ahead of the Toyota. Heidfeld is seventh with Panis and Baumgartner the only other finishers.