Marco Melandri (Aruba.it Racing - Ducati) just held off Leon Camier (MV Agusta Reparto Corse) for third place on the finish straight.
Rea was untouchable over the 20 lap contest around the 4.592km Autodromo Internacional do Algarve at Portimao as he shot away from the head of the grid and soon built up an unbridgeable lead at the front. The victory was Rea’s 18th podium in 19 races this year and the Northern Irishman now enjoys a 95 point lead at the head of the standings.
After a crash in SP2 Davies also rode brilliantly, coming from ninth on the grid to take a highly creditable second place, beating his teammate Melandri across the finish line by just under four seconds. Melandri in turn beat Camier by just +0.342 as the Brit chased him hard in the final stages of the race.
The top five also featured Michael van der Mark (Pata Yamaha Official WorldSBK Team), with Jordi Torres (Althea BMW Racing Team) sixth and Eugene Laverty (Milwaukee Aprilia) seventh.
The top ten was completed by Lorenzo Savadori (Milwaukee Aprilia), Xavi Fores (BARNI Racing Team) and Roman Ramos (Team Kawasaki Go Eleven).
There were crashes for Stefan Bradl (Red Bull Honda World Superbike Team) and Leandro Mercado (IODARacing), meaning DNFs for both, although the pair escaped their incidents otherwise unscathed.
Tom Sykes (Kawasaki Racing Team) missed the race and is out of action for the rest of the weekend after sustaining a finger injury in an FP3 crash earlier on Saturday.
On Sunday at the Prosecco DOC Portuguese Round the WorldSBK riders will go again in Race 2 at 3pm local time.
P1 - Jonathan Rea - Kawasaki Racing Team
"The weekend in general has been really positive. We've not changed the bike a lot since the test, the bike has been working really well. I have been working on myself and what I can change on the bike. We got a really good start and we made the best of the tyre, once the gap was at five seconds we aimed to pull the gap and it seemed we had extra even at the end. Riding the bike is a pleasure and I want to thank my team for the amazing package."
P2 - Chaz Davies - Aruba.it Racing - Ducati
"It was a definitely a recovery and that was what we had to hope for today. Rea's pace has been unbeatable all weekend, and it was all I could to get into the podium fight. To be honest I didn't expect to get there quite as quickly. I am happy with the result but not how the bike felt, we need to address why I couldn't extract 100% out of myself and see what we can do tomorrow."
P3- Marco Melandri - Aruba.it Racing - Ducati
"It was very difficult because I had no rear grip at the beginning of the race and the bike was very difficult to ride, with it also being unstable under breaking. I tried to break harder to improve my speed but that made it even worse. I felt I was not pushing hard and every time I pushed I made a mistake, so we will try to do better tomorrow."
#PORWorldSBK at Portimao: Race 1
1. Jonathan Rea Kawasaki
2. Chaz Davies Ducati +6.189
3. Marco Melandri Ducati +10.166