In a restarted race - after a red flag in the first Race 2 start earlier in the afternoon – Davies produced a superb ride on the Ducati, overtaking provisional leader Sykes midrace and going on to win by just under four seconds from Rea.
Davies’ first double victory of 2017 was a repeat of his Imola result from 2016, the Ducati man having also picked up maximum points at the Italian track last year.
Sykes had led the race but was eventually unable to hold off his teammate Rea for second, as the Northern Irishman ultimately beat the Yorkshirman across the line by +0.603s.
Xavi Fores (BARNI Racing Team) and home rider Marco Melandri (Aruba.it Racing - Ducati) were engaged in a close fight for fourth, with Spaniard Fores finally coming out on top in that duel by less than two tenths of a second.
Behind that pair Alex Lowes (Pata Yamaha Official WorldSBK Team) crossed the line in sixth place for more good points, with Eugene Laverty (Milwaukee Aprilia) close by in seventh. It was a solid result for Laverty after a difficult day for him on Saturday, with his big crash in Race 1.
Likewise an excellent performance by Jordi Torres saw the Althea BMW Racing Team man finish in eighth place having got away from the back of the grid, after he missed Superpole and Race 1 on Saturday due to illness.
Michael van der Mark (Pata Yamaha Official WorldSBK Team) and Leandro Mercado (IODARacing) completed the top ten, Mercado making amends for his Race 1 DNF.
There was disappointment for Leon Camier (MV Agusta Reparto Corse) who crashed out of second place early on having made a superb start, with Alex De Angelis (Pedercini Racing SC-Project) also crashing shortly after the Englishman. Stefan Bradl (Red Bull Honda World Superbike Team) was another crasher and Randy Krummenacher (Kawasaki Puccetti Racing) was forced to retire due to a technical issue.
The initial staging of the race had earlier ended in a red flag due to track conditions at turn 16, following an issue for Ayrton Badovini (Grillini Racing Team) which had left oil on track.
The WorldSBK riders will be back in action over the 26th-28th May weekend at the UK’s Donington Park circuit.
P1 - Chaz Davies (Aruba.it Racing - Ducati)
"It's been working like a dream, the bike has been in the ballpark, I made a few rebalances and used a different tyre to what I would normally use. The thing has been on rails, towards the end of the race the gap was going up and I was able to control it quite comfortably and what can I say. It's difficult to put weekends like this into perspective."
P2 - Jonathan Rea (Kawasaki Racing Team)
"Really good weekend for me, there was no stopping Chaz. We pretty much halved the gap to the front but I made a change to the front tyre, and I didn't feel really comfortable with it, it was a bit squishy but I did my best, I had fun and 40 points from Imola is a good result so I'm happy."
P3 - Tom Sykes (Kawasaki Racing Team)
"What can I say, we've always been missing that last little bit and this weekend we were really good until the racing. The track temperature today was a bit hotter and a bit greasy so I was really struggling with the front in some areas. I feel I got to the limit of what I am capable of and we need to build on this. It was a close race between the Kawasaki's all race, it's great here in front of the fans in Italy. It would have been great to have a better result but we tried."