2011 WSB champion Carlos Checa (Althea Racing) took his fifteenth race win of the season at Portimao, passing Sylvain Guintoli (Team Effenbert-Liberty Racing) with three laps remaining to take victory.
Guintoli, who finished second, rode consistently throughout the race leading from the second lap where the Frenchman managed to pass Jonathan Rea (Castrol Honda) at turn one.
Eugene Laverty (Yamaha World Superbike Team) had been running in fourth behind team mate Marco Melandri until he suffered a big tank slapper, managing to just hold on, but running off track and gifting Checa fourth. Laverty returned to the pits where his bike was examined for problems before returning to the track and finishing the race in nineteenth.
At the mid-point in the race Checa upped his pace and passed Melandri to take third, before closing in on Rea, taking a tight line and moving into second. The Spaniard then closed in on Guintoli, taking the lead with three laps remaining.
Jonathan Rea took the last step on the podium in third, whilst a resurgent ride from Max Biaggi (Aprilia Alitalia) saw the Italian move up from seventeenth on the grid to take fourth, passing Melandri who ran wide with four laps remaining and then Joan Lascorz (Kawasaki Racing Team), who took fifth, on the final lap.
Melandri finished in sixth place, ahead of Maxime Berger (Supersonic Racing Team) who put in a strong performance to finish seventh and Tom Sykes (Kawasaki Racing Team) in eighth. BMW Motorrad Motorsport rider Leon Haslam and Jakub Smrz (Team Effebert-Liberty Racing) complete the top ten at the Portugese circuit.
1. Carlos Checa (Althea Racing) Ducati 1098R 38'13.293
2. Sylvain Guintoli (Team Effenbert-Liberty Racing) Ducati 1098R 38'16.153
3. Jonathan Rea (Castrol Honda) Honda CBR1000RR 38'21.774
4. Max Biaggi (Aprilia Alitalia Racing Team) Aprilia RSV4 Factory 38'25.256
5. Joan Lascorz (Kawasaki Racing Team) Kawasaki ZX-10R 38'26.626
6. Marco Melandri (Yamaha World Superbike Team) Yamaha YZF R1 38'32.253
7. Maxime Berger (Supersonic Racing Team) Ducati 1098R 38'33.782
8. Tom Sykes (Kawasaki Racing Team Superbike) Kawasaki ZX-10R 38'38.613
9. Leon Haslam (BMW Motorrad Motorsport) BMW S1000 RR 38'39.988
10. Jakub Smrz (Team Effenbert-Liberty Racing) Ducati 1098R 38'40.094
11. Michel Fabrizio (Team Suzuki Alstare) Suzuki GSX-R1000 38'40.408
12. Leon Camier (Aprilia Alitalia Racing Team) Aprilia RSV4 Factory 38'41.856
13. Ayrton Badovini (BMW Motorrad Italia SBK Team) BMW S1000 RR 38'45.058
14. Troy Corser (BMW Motorrad Motorsport) BMW S1000 RR 38'45.115
15. Noriyuki Haga (PATA Racing Team Aprilia) Aprilia RSV4 Factory 38'45.159
16. Davide Giugliano (Althea Racing) Ducati 1098R 39'00.987
17. Mark Aitchison (Team Pedercini) Kawasaki ZX-10R 39'01.030
18. Karl Muggeridge (Castrol Honda) Honda CBR1000RR 39'19.506
19. Eugene Laverty (Yamaha World Superbike Team) Yamaha YZF R1 39'39.938
20. Santiago Barragan (Team Pedercini) Kawasaki ZX-10R 39'01.164
21. Joshua Waters (Yoshimura Suzuki Racing Team) Suzuki GSX-R1000 39'33.167
RT. Javier Fores (BMW Motorrad Italia SBK Team) BMW S1000 RR 26'33.068