Hayden also had reason to be happy however, with third overall marking a new high for a man who finished 5th and 8th in previous seasons.
Meanwhile, Rossi crossed the line 2.8secs from Hayden - depriving him of matching the all-time win record, but at least he had put the retro 50th anniversary Yamaha livery on the podium after another brilliant season for himself and the Japanese manufacturer.
Checa crossed the line 16secs later for fourth - although Barros, whose fifth place today made him just the seventh rider in grand prix history to score a career total of 2000 points, was close to depriving the Spaniard of the position - Alex having passed Biaggi with three laps to go.
All three riders - Checa, Barros and Biaggi - have yet to announce their 2006 racing plans, which are all interdependent, but one man with a clear destination for next year, Capirossi, crossed the line in a sore seventh after a brave ride on his injury comeback.
Meanwhile, eighth for Edwards secured fourth in the world championship - ahead of Biaggi, Capirossi and Gibernau - while Makoto Tamada and Toni Elias completed the Valencia top ten.
An injured Shinya Nakano rounded out the season with eleventh for Kawasaki, while BSB runner-up Ryuichi Kiyonari came within one position of matching the achievements of his Camel Honda predecessor, Chris Vermeulen, by claiming twelfth - less than a second ahead of Suzuki's John Hopkins.
Alex Hofmann completed his Kawasaki career with 14th on his injury comeback, while Ruben Xaus took the final point on what was surely his own final ride for Tech 3 Yamaha.
Joining Rolfo and Gibernau on the DNF list today were Suzuki wild-card Nobuatsu Aoki, WCM's James Ellison and Team Roberts rider Kurtis Roberts. All suffered mechanical failures
Full results to follow...