But the #65's hopes almost came to an end on lap on lap 10, when he dived inside Melandri for the lead - but nearly lost the front of his Desmosedici, forcing him to lift the machine and run wide, allowing both Melandri and Biaggi through and leaving him within grasp of Rossi.
Capirossi would be helped back into contention a few laps later when Biaggi also made a failed attempt for the lead, passing Marco cleanly at the end of the back straight, but running slightly off line on the exit, allowing the #33 to cut back past under power.
Such incidents all helped Capirossi, Rossi and Tamada to close back up to the top two and, while Biaggi would eventually force his way into the lead at the halfway mark, by then Capirossi was back in his wheeltracks and would also demote Melandri a few corners later.
Perhaps sensing that the race was starting to slip away from him, Melandri then began to make some minor errors - perhaps caused by tyre wear - such as running wide on the exit of corners, allowing Rossi and Tamada to march further towards his rear wheel.
Soon after, Capirossi attempted to outbrake Biaggi for the lead at the end of the back straight (repeating his lap one move), but was firmly repassed on the exit. However, there was much greater drama just behind them as Rossi, seeing the top two pulling away from Melandri, tried a desperately late outbraking move down the inside.
Rossi was simply too far back heading into the downhill braking area, prior to the tight right hand turn, and had no chance of stopping his M1 in time - a rare 'human error' from a superhuman rider. The result was that the Yamaha star torpedoed into the side of the unfortunate Melandri at considerable speed, hitting him as he turned towards the apex on the normal racing line.
Rossi struck the RCV near Melandri's right leg, flipping the machine and sending both riders into the gravel. To his credit, Rossi instantly rushed over to Melandri - who was holding his leg and clearly in considerable pain - to apologise and offer assistance, before being asked to move away by the track marshals.
The world champion's body language said it all as he walked slowly through the gravel with his head bowed, while Melandri was lifted onto a stretcher. It remains to be seen how badly his leg is damaged.
Melandri's exit completed a disastrous double DNF for Fausto Gresini's team, with Sete Gibernau crashing out on lap 12, while the Yamaha pits was left in an awkward silence. Rossi will have to wait until Sepang at the earliest to celebrate his latest title success - any hopes of a home Yamaha party being well and truly over.
Meanwhile, Capirossi would crawl all over Biaggi's rear wheel until launching a surprise victory pass, with 6 laps remaining, by squirting his GP5 alongside Biaggi in the middle of a double apex right hander. Loris had the inside line for the exit, made the pass and then threw everything into breaking Biaggi from his tow.