The Dutch Eredivisie match was a Semi-Final Playoff and the victory bolsters their UEFA Cup qualification hopes.
Holman finished a lovely cross from Johnny van Beukering in the 6th minute, and also created further chances later in the match.
The goal was extremely important for the Nijmegen club, who now have the upper hand over Roda. The second leg is on Sunday at NEC's de Goffert Stadium.
Only last month, Australia international Holman pledged his future to NEC.