Lucas Mahias has been reinstated as winner of the Portimao World Supersport race, following an appeal.

That in turn means title leader Sandro Cortese starts this weekend's Qatar championship showdown holding a five-point advantage over Jules Cluzel, rather than six points.

That's especially significant because it means Cortese can no longer afford to finish second to Cluzel on Saturday, since the NRT rider has more race wins and will be champion if the pair end the season equal on points.

Mahias suffered a puncture while leading on the final lap in Portimao, but the race was then stopped due to a red flag incident.

That meant the results would be taken from the end of the previous lap, when Mahias was leading.

However there are various caveats in place for classification - such as being an active participant at the time of the red flag and returning to pit lane within five minutes of a race being stopped, which Mahias was seen battling to achieve, but in the process he crucially cut out the final corner.

"I cut the last corner because I didn't want to drop fuel or oil on the track after the crashes, and it is this that got me disqualified," Mahias said at the time.

GRT Yamaha appealed the disqualification on the basis that the regulations do not specify a rider must return to pit lane via the track following a red flag, but the stewards rejected the appeal.

However, the disqualification has now been overturned after a further appeal to the CAS.

"The CAS partially reformed the Decision of the FIM Stewards by imposing a fine on Mr Mahias. Both parties will share legal costs," said an FIM statement.

"The FIM acknowledges the decision and is satisfied that the issue has been resolved without any disruption to the Championship round taking place in Doha this weekend."

Cluzel failed to finish in Portimao after being taken down by Cortese, who fell while trying to overtake his title rival early in the race. Cortese was able to remount, Cluzel was not.

Despite the extra 25-points, Mahias remains out of the title chase, sitting 28 points from Cortese. But Mahias can mathematically claim second in standings, since he is 23 points from Cluzel.