Anthony West's hopes of finishing his Kawasaki career on a high effectively came to an end after just six laps of Sunday's Valencia MotoGP season finale.

The Australian, who will switch to the World Supersport Championship with Stiggy Honda in 2009, came into the final round aiming to beat team-mate John Hopkins for the fifth time in the last seven races.

West qualified just 17th on the grid, ahead of only his 2009 replacement Marco Melandri, but was up to 13th by lap three.

Rear traction issues that have haunted West and Kawasaki all season then began to kick in, amplified by a 'questionable tyre choice' and he slipped steadily back to last position by lap 14 of 30.

The 27-year-old's only consolation thereafter was to overtake an equally struggling Toni Elias on lap 24.

"What a frustrating end to a frustrating season," said Ant. "I wanted to finish my last race with Kawasaki as close to the top ten as I could, but a questionable tyre choice put paid to that today. Rear grip dropped off sharply within a few laps, and it was like riding dirt track for the rest of the race with the bike sideways everywhere."

West, who joined Kawasaki midway through the 2007 season, then reflected on his time at Team Green - whose 2008 spec ZX-RR proved uncompetitive from the start.

West scored 59 points from eleven starts last season, but managed just 50 from the full 18 rounds of this year's contest, leaving him 18th and last of the full time riders, but only seven points behind Hopkins and just one behind Melandri.

"This season didn't turn out as I was expecting, and while I'm sure people are pointing the finger at me for this, I leave here knowing that I did my best and that I couldn't do any more," said West.

"I knew I'd finish the season close to my team-mate in the championship standings, what I didn't expect was for us both to be so close to the bottom of the points table.

"I'd like to thank Kawasaki for giving me this chance in the premier class; it hasn't been the easiest time, but the experience will definitely stand me in good stead as I move onto pastures new in 2009," he concluded.

"I'd like to thank Anthony for all his hard work this year and, together with everyone in the team, wish him the best of luck for next season," said Kawasaki competition manager Michael Bartholemy.

Both Hopkins and West took a best race finish of fifth this year.