Promoting Biaggi up to seventh place, that soon became sixth when Leon Haslam ran on at Lycee and slipped from fourth place down to seventh.
In fact, Haslam's error would prove pivotal in the fight for the title, the mistake putting fifth place, which was several seconds up the road beforehand, now in sight of Biaggi.
Taking immediate advantage, though Biaggi didn't help his cause when he ran wide at Lycee on lap eight and slipped behind Giugliano again, he would use the superior straight line pace of the RSV4 to pass the first Althea Ducati on lap 13 before pulling a similar move on Checa on lap 15.
A fitting pass for the championship on the outgoing champion, Biaggi steadily extended his advantage over the Althea Ducati pair knowing that he just had to stay where he was to seal the title.
Further up the road, Sykes was doing everything he needed to do up at the front, keeping Sylvain Guintoli and then Jonathan Rea at bay from start-to-finish to complete his fourth win of the season.
Immediately turning around to see where Biaggi would cross the line, though the Italian would come through 13 seconds behind, the 11 points for fifth place were exactly what he required to hold off his rival by the very smallest of margins.
Delight for Aprilia, who have also been crowned manufacturers' champions, it is the second WSBK title of Biaggi's career and his sixth motorcycle world championship.
By contrast, it is an agonising conclusion for Sykes, who will no doubt rue the fact he was only awarded half-points for his win at Monza earlier in the season. Indeed, while the Kawasaki rider will be thrilled to finish as runner-up, it is a bitter end to an otherwise magnificent breakthrough season.
Amidst all the drama of the title fight, Rea secured a welcome podium after his dramatic exit from the first race, while race one winner Guintoli completed his second podium of the day in third, in doing so snatching seventh in the overall standings from Haslam, who eventually crashed out.
Laverty hung back in fourth position ready to swap places with team-mate Biaggi if required, before deciding to keep the place himself.