Kawasaki rider Tom Sykes was unable to hold off reigning world champion Carlos Checa in race one at Imola despite leading the first half of the race.
Sykes got the holeshot from pole position, and looked comfortable in the lead for the first half of the race, before Checa took the lead on lap 12 and then set a new lap record with a time of 1:47.877.
Sykes said: "The plan was to get a good start and I surprised myself with a clean start. For the first nine laps it was just myself and Carlos.
"Carlos rode a great race - I knew exactly what he was doing sitting behind me and when it was time to go he just went and I had no answer.
"Definitely the cold conditions have played a part in tyre choice and wear. I hope we can make one or two changes for the second race."
Checa's second victory of the season sees him close the gap on championship leader Max Biaggi to nine points.
Factory BMW rider Leon Haslam snatched the final step on the podium from Max Biaggi with just three laps to go. On the second lap Haslam passed Frenchman Sylvain Guintoli, pushing him wide and causing a collision between Guintoli and WSB newcomer Chaz Davies.
Biaggi's team-mate Eugene Laverty finished fifth, after a race long battle with Jonathan Rea, ninth, and Lorenzo Zanetti, eighth.
Brit Leon Camier failed to finish the race after a first lap crash. Team-mate John Hopkins finished 13th on his first race back from injury.
1. Carlos Checa (Althea Racing) Ducati 1098R 38'06.264
2. Tom Sykes (Kawasaki Racing Team) Kawasaki ZX-10R 38'09.470
3. Leon Haslam (BMW Motorrad Motorsport) BMW S1000 RR 38'11.857
4. Max Biaggi (Aprilia Racing Team) Aprilia RSV4 Factory 38'12.783
5. Eugene Laverty (Aprilia Racing Team) Aprilia RSV4 Factory 38'30.926
6. Marco Melandri (BMW Motorrad Motorsport) BMW S1000 RR 38'33.525
7. Joan Lascorz (Kawasaki Racing Team) Kawasaki ZX-10R 38'33.648
8. Lorenzo Zanetti (PATA Racing Team) Ducati 1098R 38'34.563
9. Jonathan Rea (Honda World Superbike Team) Honda CBR1000RR 38'40.331
10. Niccolò Canepa (Red Devils Roma) Ducati 1098R 38'41.988
11. Jakub Smrz (Liberty Racing Team Effenbert) Ducati 1098R 38'43.002
12. Maxime Berger (Team Effenbert Liberty Racing) Ducati 1098R 38'43.521
13. John Hopkins (Crescent Fixi Suzuki) Suzuki GSX-R1000 38'56.682
14. Leandro Mercado (Team Pedercini) Kawasaki ZX-10R 38'59.887
15. Ayrton Badovini (BMW Motorrad Italia GoldBet) BMW S1000 RR 39'00.206
16. Brett McCormick (Liberty Racing Team Effenbert) Ducati 1098R 39'00.403
17. Mark Aitchison (Grillini Progea Superbike Team) BMW S1000 RR 39'04.208
18. Hiroshi Aoyama (Honda World Superbike Team) Honda CBR1000RR 39'12.497
19. David Salom (Team Pedercini) Kawasaki ZX-10R 38'08.075
RT. Michel Fabrizio (BMW Motorrad Italia GoldBet) BMW S1000 RR 14'55.953
RT. Davide Giugliano (Althea Racing) Ducati 1098R 15'15.537
RT. Sylvain Guintoli (Team Effenbert Liberty Racing) Ducati 1098R 1'51.678
RT. Chaz Davies (ParkinGO MTC Racing) Aprilia RSV4 Factory 1'53.395
RT. Leon Camier (Crescent Fixi Suzuki) Suzuki GSX-R1000
RT. Lorenzo Alfonsi (Team Pro Ride Real Game Honda) Honda CBR1000RR