It meant Ducati Xerox would end the season with a 1-2 finish, but it wasn't enough for Haga to keep the title in their hands for a second successive season as, just a few seconds behind, Spies was crossing the line in fifth position to confirm himself as the 2009 Superbike World Champion in his rookie year.
With a MotoGP debut for Tech 3 Yamaha beckoning next month, Spies's title win follows up Valentino Rossi and Cal Crutchlow's success earlier in the day. Furthermore, having never won a World Superbike title in 21 years, this could be considered the sweeter triumph.
As it stands, Spies won the title with 14 race wins, 11 pole positions and 462 points, a record-breaking feat that even puts him 14th on the all-time list after just one season.
A dejected Haga finishes as runner-up for the third time in his career (and inside the top three for the seventh time), but is likely to start as hot favourite for the 2010 title following Spies' defection to MotoGP.
Elsewhere, Rea's final lap error cost him the chance to pass Biaggi for fourth in the overall standings, the pair settling for third and sixth in the race to give the Italian the advantage at the end of an impressive season for series returnees Aprilia.
Away from the drama at the front, Camier posted his second excellent result of the day in seventh, just two seconds behind Biaggi, to give himself a good chance of remaining with Aprilia into 2010.
He was finished ahead of Jakub Smrz, Troy Corser
and Sylvain Guintoli, who signalled his arrival to World Superbikes with a fine run to tenth, ahead of the man he replaces at Suzuki 2010, Yukio Kagayama.
Broc Parkes signed off for Kawasaki with two points' finishes in 12th, ahead of Matthieu Lagrive, Luca Scassa and David Checa.