Eredvisie: Heerenveen 5 RKC Waalwijk 2
Marco van Basten's men went into the game looking to end a run of three straight Eredivisie defeats by beating struggling RKC.
And it was top scorer Finnbogason who inspired them to an easy victory, with the Iceland international striker taking his tally for the season to 14 goals in 11 top-flight fixtures this term.
Defender Kenneth Otigba opened the scoring 11 minutes before half-time as he volleyed home Hakim Ziyech's cross from close range.
Finnbogason doubled the lead from the spot three minutes into the second half, before seemingly putting the game beyond doubt with his second.
French forward Jean-David Beauguel looked to have given RKC hope when he pulled one back, only for Finnbogason to complete his treble with another penalty.
Ziyech capped an impressive performance with a superb long-range lob five minutes from time, with Michael Lamey's late header little more than a consolation for RKC, who had defender Ingo van Weert sent off for a second bookable offence in injury time.