Hiroshi Aoyama will head into the final round of the last ever 250cc World Championship with a dominant 21 point advantage over Marco Simoncelli, after a hard earned victory at Sepang in Malaysia on Sunday.

French privateer Jules Cluzel turned his first ever front row start into the race lead at turn one, and did his growing reputation no harm at all by continuing to head the field until being overtaken by Simoncelli on lap four of 20.

Reigning champion Simoncelli had fought has way forwards from just eighth on the grid, including a lunge inside Aoyama on lap three.

Aoyama, who began the race with a 12 point lead over Simoncelli on the day of his 28th birthday, had dropped back to fourth after a botched attempt to take the lead from Cluzel early in the race - but a far neater pass on lap five put the Scot Honda rider second only to Simoncelli.

Aoyama then dived for the lead into the final hairpin, but Simoncelli kept the inside line and chopped firmly across the Japanese on the exit - forcing Aoyama over the kerb.

Aoyama shook his head in obvious displeasure at the incident, and momentarily lost second to Cluzel soon after, but had regrouped and regained second by the end of the lap.

The #4 repeated the hairpin move with more success on lap eleven - but was repassed by Simoncelli on the home straight, pushed Simoncelli wide at turn one and then lost out to Simoncelli again at turn two!

Aoyama's next attack came with a surprise pass on lap 13, prompting a repeat of the side-by-side action through turns one and two, which this time ended with Aoyama on top.

A later lunge by Simoncelli was also rebuffed and Aoyama had gained vital bikelengths over Simoncelli and the spectating Hector Barbara with six laps to go.

Simoncelli had been desperate to prevent Aoyama exploiting his raw Sepang speed, but that was exactly what the Japanese was able to do in the closing stages, building a one-second lead with five laps to go before riding to a vital fourth victory of the season by 6.397sec

Barbera fumbled his first attempt to pass Simoncelli, but the marauding Pepe World Aprilia rider remained a threat and an inside pass at the final hairpin ended with a final hairpin showdown and a photo-finish at the line!

A lengthy video review followed before Race Direction declared that it was a dead heat, but that Barbera had been awarded second position over the Metis Gilera rider because of a faster race lap.

Tellingly, just as one year ago (when he had clinched the title at Sepang) an exhausted Simoncelli was left gasping for water at the end of the race, while Aoyama celebrated enthusiastically. Simoncelli sportingly hugged the Japanese in parc ferme.

Cluzel's heroics came to an upsetting end when he fell from third at the halfway mark, while a nightmare race for the Aspar Aprilia team saw Mike di Meglio and then Alvaro Bautista lowside out of the lead group on lap five and six respectively, mathematically ending Bautista's slim title hopes in the process.

Indeed, Bautista has now lost third in the championship to Barbera.

After a near fall at turn one, Swiss Thomas Luthi charged all the way up to fourth position for Caffe-Latte Aprilia.

Race results - Sepang:

1. H. Aoyama (Honda)
2. Barbera (Aprilia) +6.397sec
3. Simoncelli (Gilera) +6.397sec
4. Luthi (Aprilia) +14.871sec
5. Faubel (Honda) +19.177sec
6. Wilairot (Honda) +19.567sec
7. Debon (Aprilia) +20.255sec
8. Pesek (Aprilia) +34.567sec
9. Baldolini (Aprilia) +50.937sec
10. S. Aoyama (Honda) +1min 4.186sec