The 31-year-old sprinter won a race to the line after being well led out by British Omega Pharma-QuickStep team-mate Andy Fenn.
Kris Boeckmans (Vacansoleil-DCM) and Boy Van Poppel (UnitedHealthcare) finished second and third respectively.
The 67th edition of the Belgian race, a 195.5km route, began with a minute's silence for the Belgian victims of a bus crash earlier in the day in Switzerland which has claimed 28 lives.
When racing began the sprint finish looked inevitable, with Chicchi's team doing their best to control the final stages, and Chicchi using his route knowledge to place himself perfectly coming out of the final corner.
Chicchi has already claimed two stage victories on the Tour de San Luis this year, as well as triumphing on the first stage of the Driedaagse van West-Vlaanderen.
“Today I was going very well and I knew the finish too as I'd done it a few times in the past,” Chicchi said afterwards. “My team was fantastic as always and believed in me.”