The #27 LCR rider, desperately chasing his first ever GP victory, would hold the top spot all the way to the penultimate lap – by which time Jenkner and Barbera were battling hard for second, pulling away from fourth placed Simoncelli in the process.
The last lap began with Stoner just 0.279secs clear of Barbera, and the local hero would dive inside for the lead at turn two – but run wide – and allow Casey back ahead.
However, with 120,000 fans urging him on, there was no way Hector would settle for second and it was only a matter of when, not if, he made his move. But with Stoner riding faultlessly, Barbera faced a tough task and with time fast running out he gambled on a gutsy 'around the outside' move on the off-camber run into the final turn.
Barbera ignored the laws of physics to surge ahead, but there was no way he could make the corner and ran wide again – losing both the race to Stoner, and second to Jenkner, as a result.
The normally cool Casey couldn't contain his delight at finally breaking his GP duck and he crossed the line with his fist in the air. It was a 'perfect' win, since he can now take the victory with him all the way to South Africa at the end of April 2004.
Behind the top three, Perugini fell in the closing laps, allowing Simoncelli, de Angelis, Bautista, Nieto and Dovizioso to complete the top eight.
Outside of the finishing order, Valencia saw two 125cc heroes say goodbye to GP racing – local star Emilio Alzamora taking an emotional tribute lap to thank his fans after crossing the line 24th, while Lucio Cecchinello (Stoner's team owner) was left crying for Italy in the pit garage as his LCR team applauded him after finishing ninth on his final race.
Cecchinello would later storm the podium to congratulate Casey – and steal some of his champagne – while injured world champion Dani Pedrosa was also present, to rather bizarrely accept an award for top 125cc privateer!
Meanwhile, despite his fall, de Angelis kept second in the championship over Barbera, who would have kept the position had he not tried to overtake Stoner – but Hector probably wouldn't even be here if he thought that way.
Full results to follow...
5. de Angelis