Valentino Rossi will go down in history as the last rider to win a 500cc GP after a thrilling two part Rio Grand Prix, which saw the race stopped due to rain after four laps, before the remaining 20 were run.

The second part decider saw Carlos Checa carve his way through the field to take the lead from new World Champion Rossi, with Max Biaggi also left in the Spaniard's wake. Despite Vale's best efforts Checa looked to have the race sewn up - until the very final corner and a backmarker...

Tohru Ukawa had upset the establishment yesterday by becoming the first non-Italian rider to take pole position this year, with the pinnacle of a superb series of quick laps proving enough to hold off the challenge of Loris Capirossi and Kenny Roberts, who qualified in second and third respectively.

Completing the front row was Shinya Nakano, ahead of new World Champion Valentino Rossi, Sete Gibernau, Carlos Checa and Olivier Jacque, while normally dominant qualifier Max Biaggi, who could lose second place in the championship if he were to score five points less than Capirossi today, qualified in tenth - despite briefly flirting with top spot.

So this was it: The last ever 500cc Grand Prix, and the last of the 2001 season - a year that had seen some of the closest, most thrilling, races in the sport's history and a fitting end to the exclusive half litre class before big bore 4-strokes join the fight next year.

Adding to the tension was the fact that the weather in Rio had been decidedly 'dodgy' today - resulting in the 500cc warm-up being run in wet conditions - and with Jurgen van den Goorbergh setting the pace in his last ride with Team KR, ahead of Rossi and Kenny Roberts, while V-Twin rider Anthony West had impressed in the tricky conditions.

Approximately 3hours later at 2.00pm local time, and with the track now effectively dry, the red lights went out for the final time at the start of a 500cc Grand Prix - sending the 21 rider field charging into the first turn with Roberts leading the way from Ukawa - but behind them Jacque lost control of his Tech 3 Yamaha under braking and high sided at the apex, unfortunately (and embarrassingly) collecting his teammate Shinya Nakano and sending them both into the gravel, although Nakano would rejoin.

Jacque's crash allowed Roberts and Ukawa to break away slightly from their pursuers - Capirossi, Rossi, Checa, Abe, Biaggi and Barros.

Onto the long back straight on lap two and Ukawa calmly pulled out of Roberts' slipstream to slip effortlessly ahead of the American and into the lead of the Rio Grand Prix.

But behind them Rossi was on the move and soon catching the top two, prompting Roberts to put an aggressive move on Ukawa to regain the lead and try to keep Rossi at bay. Keeping pace with the Italian was Carlos Checa, the Marlboro Yamaha star having been off pace in GP's of late, but certainly making amends in the early stages in Brazil.

The crowd though only had eyes for local hero Alex Barros and their support soon helped spur the West Honda Pons pilot up to fifth behind Checa after edging out his teammate into the final turn on lap 3.

By lap 5 Roberts had lost the lead once again to Ukawa along the back straight as Honda horsepower lead the way, while Suzuki's hopes (looked to have) worsened when Gibernau crashed out a lap later.

Meanwhile, Barros was charging through the order - passing Biaggi and Rossi in quick succession as the temperature rose in the grandstands. Unfortunately, the weather was doing anything but and race leader Ukawa soon raised his hand to signal rain was falling on the 4.9km circuit, the race being red flagged with the standings taken after 4 laps - meaning an aggregate result - and allowing Gibernau back into the action.

Fortunately, as the riders returned to the pits, the rain was not getting any worse and the 20 lap second part of the Rio Grand Prix, which would start at 2.40 local time, would almost certainly be run in hard to predict damp conditions, with the shower now having blown over towards the misty mountains in the distance.

When the field assembled for the second time it was in the order they had been in one lap before the red flag was waved, meaning that Ukawa sat on pole once again, with Roberts second ahead of Rossi, Checa, Barros, Capirossi and Biaggi.

Giving the teams' plenty to think about before the start was the all-important choice of tyres - should they go for intermediates, slicks or a combination of both...? The moisture on the track at that time was caused by no more than drizzle - but would the weather get worse or better...? The next 20 laps would be too close to call.

By the time the red lights were lit most of the riders had opted for combinations of slightly cut slicks and intermediates, with many feeling that although the track wasn't wet as such, the moisture would make the surface particularly greasy. This had prompted Suzuki's Roberts to choose wet tyres, in the hope that the weather would get worse, but the track looked to be drying as the drizzled all but disappeared...

When the lights went out, it was Checa who lead teammate Biaggi around the first corner, but McCoy was the man on the move as he shot from the third row to third at the first turn before taking Biaggi at the next turn and the Checa for the lead immediately after!

However, hanging on to the Australian's rear was Rossi who revelled in the conditions to take the lead himself one lap later - while Roberts pulled into the pits as the Californian realised his error in choosing wets. He would return soon after, when he realised that a change would be pointless.

Back on track and the Repsol Honda's were now battling tooth and nail for second as the Spaniard put in a fitting final performance on HRC machinery. That battle came to a head on lap 7 (overall) when Ukawa and Criville went side-by-side into turn one and the Japanese rider lost the front of his NSR and slid into the gravel, handing Rossi the overall lead from fast catching Barros, who was now up to second both on track and overall.

Behind Barros, Biaggi was beginning to hound Alex Criville for third, eventually succeeding in passing the 1999 World Champion into turn one on lap 9, but it was Biaggi's teammate Checa (fifth on track ahead of Abe) who was third overall.

To the delight of the fanatical locals Barros began catching Rossi, the Brazilian needing to find 1.8secs to both beat Rossi on track AND take the overall victory.

Reinforcing his claim for third was Checa, who swept inside Criville for fourth and was immediately on Biaggi's rear wheel (even though in the overall standings he was already ahead of the Italian) by lap 11, as he set the fastest lap of the race.

The top four began to break away from Criville over the next few laps, with Checa now looking like a serious challenger for victory with Biaggi the joker in the pack as although he worked his way up to second by lap 13, he was still 2.8secs behind Rossi overall.

This allowed fourth placed Checa to move ahead of Barros (now ahead of him in third on track) while the Spaniard was now just 0.6secs behind race leader Rossi overall, as another Biaggi/Rossi battle began up front.

One lap later and Checa pushed Barros back to fourth as he slotted in behind Biaggi, and edged ever closer to Rossi (the gap between the #7 and #46 machines now being 0.5secs overall) as the top four continued to circulate nose-to-tail.

Checa now began to look eagerly for a way past his teammate, and did so with 10 laps left, with the sometimes inconsistent Spaniard putting in his best race since his second place behind Biaggi in Germany.

Checa completed his charge by taking the lead one lap later into turn one, giving him both the overall and on-track race lead, while Biaggi began to worry his arch rival. Meantime, Barros was being punished for his relatively wet set-up and had slipped away from the top three, allowing Biaggi to move ahead of him overall and meaning that the top three on track were now (thankfully) in that order overall, while Abe, Capirossi and Criville battled it out for fifth on track, and with the exception of Criville, overall.

Over the next few laps gap between Checa and Rossi see-sawed around the 0.2secs mark, with Biaggi actually dropping off slightly as the top two punched out their fastest laps of the race.

Lap 23 of 24 and both Checa and Rossi's machines were weaving violently as they tried to get the power down earlier than the other, with Biaggi now out of the picture and over 4secs adrift.

Onto the last lap and Rossi desperately attempted to slipstream the Yamaha at the end of the back straight, but Checa shut the door. Both riders then slid their way around the rest of the circuit - until they caught Anthony West on the last corner...

Checa wound the power on and went around the outside of the Australian, but Rossi had more momentum and although Checa won on track, Rossi took the overall win in the last ever 500cc Grand Prix by just 0.143secs, even though he finished half a bike length behind the devastated Marlboro Yamaha rider at the flag.

Behind them Biaggi took a 'safe' third, while by contrast Barros banged fairings with his teammate Capirossi as he dived inside the Italian around the final corner - which allowed Abe to slip by the pair of them on track - but Barros still grabbed fourth overall.

The completion of the two part Rio Grand Prix therefore signalled a suitably thrilling end to the two stroke domination of the World Motorcycle Championship, and paves the way for the exciting addition of four strokes next year - but with plenty to live up to.

Full results to follow...

Overall standings

1. Rossi
2. Checa +0.143secs
3. Biaggi +6.980secs
4. Barros +19.053secs
5. Capirossi +20.655secs
6. Abe +20.829secs
7. Criville +27.894secs
8. Cardoso +45.110secs