With Dordrecht - promoted to the top flight last season - losing 3-0 at Vitesse on Saturday, Dennis Demmers' men knew that an unlikely victory at De Kuip on Sunday would see them safe from automatic relegation.
And the division's second bottom club - who had lost their last seven games - duly delivered the goods.
Jules Reimerink's cool near-post finish in the 71st minute proved enough for the visitors to go 10 points ahead of Dordrecht with only three games remaining.
Meanwhile Heracles boosted their survival hopes by going further clear of the relegation play-off zone with a 2-0 victory over PEC Zwolle, who had Trent Sainsbury sent off in the 52nd minute.
That win moves Heracles three points ahead of third bottom NAC Breda following their 0-0 draw with deposed champions Ajax at the Amsterdam Arena.
Ajax could not give their fans a consolation to celebrate after Feyenoord claimed the title on Saturday, with 10-man NAC holding out despite seeing Gill Swerts dismissed in injury time.
Elsewhere, Utrecht beat Twente 1-0.
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