Thor Hushovd had been favourite to win, but Vacansoleil's van Hummel held off team-mate Barry Markus for the win.
Rudiger Selig came third, with Husovd down in fifth.
Stage one results:
1 Kenny van Hummel (NED) Vacansoleil 4:23:45
2 Barry Markus (NED) Vacansoleil +0
3 Rüdiger Selig (GER) Katyusha +0
4 Thor Hushovd (NOR) BMC Racing +0
5 Jetse Bol (NED) Belkin +0
6 Jonas Ahlstrand (SWE) Argos +0
7 Jo Ringheim (NOR) People4you +0
8 Sondre Enger (NOR) Plussbank +0
9 Ralf Matzka (GER) NetApp +0
10 Jan Ghyselinck (BEL) Cofidis +0