The Belgian raced ahead of Italian Valerio Agnoli (Astana) and Spaniard Alejandro Valverde (Movistar) to take the victory after the 159.3km trek.
A frisky looking Bradley Wiggins (Team Sky) broke up the peloton on the final descent and earned 28 seconds on some of his rivals.
Flanked by team-mates Dario Cataldo and David Lopez, the Tour de France winner led the peloton to the finish before eventually finishing sixth in a group of 13.
However, fellow GC contenders such as Joaquim Rodriguez (Katusha), Robert Gesink (Blanco Cycling), Michele Scarponi (Lampre-Merida) and Valverde were all amongst the leading bunch.
Meersman's victory sees him take the early lead in the six-stage race thanks to his time bonus.
Amongst the GC contenders, Valverde struck the first blow as he gained four bonus seconds for his third-place finish.
Stage two is a 160.7km trek from Girona to Banyole on Tuesday.
Eurosport will be showing six-and-a-half hours of live racing throughout the week with the conclusion of six of the seven stages brought to you live by Sean Kelly and David Harmon.
