Colbrelli sat poised behind last year's winner, Peter Vakoc (Quickstep) at third wheel, waiting to launch his attack on the flat, final straight after the Schavei berg at the finish in Overijse.
In the end, the Italian powerhouse just had too much for Vakoc and Tiesj Benoot (Lotto Soudal) as he worked his way through an opening to cross the line several bike lengths ahead.
“I wanted to win so much after such an aggressive race," Colbrelli said. "I was nervous because I did not want the peloton to catch us and in the sprint I was worried that I’d lost it because Vakoc squeezed me into the barriers, but finally I found the space and managed to win.
"Last year I was close to win and this time I succeeded. My aim was to do well today and then on Sunday on Amstel Gold Race. Let’s see, how it will go,” he said.
As the peloton stared down the early six rider breakaway group with around 40 kilometres to go, Colbrelli launched a counter attack from the peloton with around 12 riders that included the likes of team mate Grega Bole, Benoot, Silvan Dillier (BMC) and Christopher Juul-Jensen (Orica-Scott). The group soon enjoyed a 30 second advantage.
As the gap drastically reduced to around 12 seconds with 15 kilometres to go, defending champion Vakoc was able to bridge across to the escapees with Tim Wellens (Lotto Soudal) who jumped from the bunch on the final lap of the race circuit.