Second seed Fernando Verdasco, the highest-ranked player in the field following the withdrawal of David Ferrer, recovered from a slow start to beat Paul-Henri Mathieu 2-6 6-4 6-4 in the opening round of the Topshelf Open.
Verdasco prevailed to set up a second-round clash with wildcard Jesse Huta Galung, while fellow Spaniard Ferrer will not feature after pulling out due to illness.
Having offered Frenchman Mathieu seven break points in a disappointing first set, Verdasco bounced back to win a break in both of the remaining sets to claim victory.
Dutchman Huta Galung reached the last 16 after Ukraine-born Aleksandr Nedovyesov was forced to retire, despite being a set and a game up.
Spanish third seed Roberto Bautista-Agut breezed through with a routine 6-1 6-3 win over Daniel Gimeno-Traver.
However, Halle finalist Alejandro Falla was unable to repeat last week's heroics as he was dumped out at the first hurdle by eighth seed Juergen Melzer of Austria.
Portugal’s Joao Sousa came through a three-set battle with Italian Paolo Lorenzi to prevail 6-3 3-6 6-3 as he set up second-round clash with fellow qualifier Mate Pavic.
Croatian Pavic beat Colombia’s Alejandro Gonzalez 7-6 (6-4) 6-3 and the winner of his last 16 showdown with Sousa faces a potential quarter-final against 2011 champion and fifth seed Dmitry Tursunov.
Despite qualifying for five of the last six Grand Slams, Czech Lukas Rosol could not progress beyond the first round in Hertogenbosch as he fell to a 6-4 6-2 straight-sets defeat to Jan-Lennard Struff of Germany.