Lorenzo triumphs in Estoril (UK only)
World champion Jorge Lorenzo held off a strong challenge from Yamaha team-mate Valentino Rossi to win the Portuguese MotoGP for the third year in a row.
The Yamaha rider, 23, who took the world crown from Rossi in Sepang on 10 October, came out on top again.
Honda rider Andrea Dovizioso grabbed third on the line in Estoril in the penultimate race of the season.
Lorenzo overtook Rossi with 11 laps to go before speeding clear for an 8.6-second victory over the Italian.
It was the Spaniard's first victory in two months and he can wrap up the season with a win on home soil in Valencia next Sunday.
The race was held in perfect, dry conditions, but that did not prevent Ducati's Casey Stoner, fourth on the starting grid, from slithering off the circuit after just five laps.
Stoner subsequently lost his third position in the overall standings to Rossi.
For Lorenzo, who started on pole, this was his eighth race win of the campaign and it pushed him up to 368 points. Dani Pedrosa, only eighth here, is second on 236.
Rossi and Lorenzo battled for control from the start, but once Lorenzo hit the front on lap 17 of 28 he never looked back.
Lorenzo said afterwards: "Valentino overtook me [after four laps] and got away from me for a while, but I stayed calm and began reeling him in bit by bit."
Lorenzo pleased to conquer conditions (UK only)
Rossi said: "It's a particular kind of race. On the dry surface I lacked some speed and I couldn't keep up with Jorge."
German rider Stefan Bradl of Suter edged Alex Baldolini to win his first Moto2 race of the season.
And in a fascinating 125cc race, Marc Marquez - who started at the back of the grid after crashing during the reconaissance laps - passed all but two of the 16 bikes in front of him within the first lap before charging to victory.
Bradley Smith from Oxford finished third in the 125cc race and has
confirmed his move up to the Moto2 class for 2011 via his Twtter feed.
Smith will race for the French-based Tech3 Racing team alongside Mike di Meglio and join fellow British rider Scott Redding in the Moto2 championship.
1. Jorge Lorenzo (Spain) Yamaha 46mins 17.962secs
2. Valentino Rossi (Italy) Yamaha 46:26.591
3. Andrea Dovizioso (Italy) Honda 46:44.437
4. Marco Simoncelli (Italy) Honda 46:44.496
5. Nicky Hayden (U.S.) Ducati 46:45.116
6. Randy de Puniet (France) Honda 46:46.259
7. Colin Edwards (U.S.) Yamaha 46:48.071
8. Dani Pedrosa (Spain) Honda 47:02.909
9. Marco Melandri (Italy) Honda 47:31.611
10. Hector Barbera (Spain) Ducati 47:35.683
11. Alvaro Bautista (Spain) Suzuki 47:35.870
12. Hiroshi Aoyama (Japan) Honda 47:50.987
13. Loris Capirossi (Italy) Suzuki 47:57.714
UNPLACED Carlos Checa (Spain) Ducati 13 Laps
Casey Stoner (Australia) Ducati 4 Laps
1. Stefan Bradl (GER) Suter 46min 59.723sec
2. Alex Baldolini (ITA) ICP at 0.068sec
3. Alex De Angelis (RSM) Motobi 2.830
4. Scott Redding (GBR) Suter 2.842
5. Kenan Sufuoglu (TUR) Suter 2.947
1. Marc Marquez (Spain) Derbi 16mins 27.878secs
2. Nicolas Terol (Spain) Aprilia 16:28.028
3. Bradley Smith (Britain) Aprilia 16:28.090