Ajax Amsterdam, 2-0 winners at NAC Breda on Saturday, are top with 70 points after 32 matches and will clinch their third straight title if they beat strugglers Willem II Tilburg at home next week in their penultimate game.
PSV Eindhoven, 5-2 winners over Groningen on Saturday, remain second with 66 points and ahead of Feyenoord on goal difference while Vitesse Arnhem follow on 64 after beating Tilburg 3-1 on Sunday.
Second spot in the Dutch league is worth a Champions League qualifying place with third and fourth heading for the Europa League.
Goossens opened the goalfest when he fired a free kick around the wall and into the top corner of the net after 19 minutes before Pelle doubled the lead with a superb finish from outside the penalty area.
Lex Immers added a third followed by Pelle's 26th league goal of the season when he converted a penalty after Heracles goalkeeper Remko Pasveer was sent off on the stroke of halftime.
Ruben Schaken and Goossens completed the rout in the second half.
"We knew that Heracles dared to play offensively and it took us a while before we realised and adapted to create chances using our speed up front," said coach Ronald Koeman.
"Now a win next week (away at ADO Den Haag) and then we are close to finishing second seeing the schedule of PSV."
Feyenoord will then host NAC Breda on the final day, while PSV first play NEC Nijmegen at home before they travel to Twente Enschede.
Mike Havenaar put Vitesse ahead after nine minutes why he netted from close range before Wilfried Bony doubled the lead with his 31st of the season. Marco van Ginkel made it 3-0 followed by a consolation goal from Genaro Snijders.
Twente cruised a 5-2 home win over NEC Nijmegen to stay fifth on 58 points, one ahead of Utrecht who beat PEC Zwolle 2-1 away.
Both sides have qualified for the Dutch playoffs for a third place in the Europa League.