2009 125cc world champion Julian Simon has won the final race of the season, after exchanging the lead with team-mate Bradley Smith three times on the last lap at Valencia.

Smith suffered a scare when his bike stopped on the warm-up lap, but the double 2009 race winner got his Aspar Aprilia restarted just in time to take up third on the grid.

The interruption certainly didn't do the Englishman any harm as he rocketed off the line to take the holeshot at turn one, then pulled a 1.4sec lead over Simon by the end of the first lap!

Simon was initially hampered by attacks from Marc Marquez, but once able to escape he quickly closed down Smith's lead and was locked onto the Englishman's back wheel by lap 5 of 24.

The Aspar riders rode in formation into the distance, holding a seven second lead as the halfway point came and went.

Simon had snatched victory from Smith on the last lap of the two previous events, a thought that must have been weighing heavily on Smith's mind as the Spaniard sat patiently behind him for lap after lap.

On the other hand, Simon's two previous events on home asphalt had ended with the #60 crashing out at Jerez then celebrating one lap early in Catalunya.

This time it was Smith who made the mistake, running wide with four laps to go and gifting Simon the lead - but the #38 battled back to within striking distance as the last lap began.

The Englishman, desperate to beat Simon in their last race together for at least a season, made a lunge for the lead early in the lap, but Simon cut straight back inside on the exit. Smith then struck again under braking at the end of the back straight, only for Simon to nip back past through the twisty sections.

That set up a last turn showdown, with late-braking star Simon taking a defensive inside line, while Smith opted for a wide entry to try and blast past on the exit. It didn't work and Simon held on for his seventh win of the season and last in 125 before switching to Moto2 next year.

Smith, already confirmed as second in the championship, collected his sixth podium in a row and will return to 125GP with Aspar next season.

Double 2009 winner Pol Espargaro spent most of the race in a lonely third for Derbi and, although he gained ten points on Nicolas Terol, it wasn't enough to deprive the Jack & Jones Aprilia rider of third in the final standings. Terol will join Smith at Aspar next year.

A thrilling seven-rider fight for fourth went right to the flag with Simone Corsi on top by just 0.34sec from Marcel Schrotter - who marked himself out as a future star with a combative ride in only his fourth grand prix for the Toni Mang Honda team.

KTM's last race in 125GP ended far less successfully, with Marquez being torpedoed by Joan Olive on the last lap, costing him a shot at fourth before limping home in 17th.

Scott Redding wiped out Blusens Aprilia team-mate Esteve Rabat at the final turn early in the race. Fellow Briton Danny Webb, who will ride for Jack & Jones Aprilia next season, withdrew from the race due to broken bones in both feet sustained at Sepang and then qualifying at Valencia.

Race results - Valencia:

1. Simon (Aprilia)
2. Smith (Aprilia) +0.220sec
3. Espargaro (Derbi) +12.123sec
4. Corsi (Aprilia) +17.577sec
5. Schrotter (Honda) +17.917sec
6. Olive (Derbi) +18.334sec
7. Vazquez (Derbi) +18.502sec
8. Cortese (Derbi) +18.553sec
9. Krummenacher (Aprilia) +18.731sec
10. Terol (Aprilia) +21.280sec

Redding (Aprilia) DNF
Webb (Aprilia) DNS