The first top-flight meeting between the two sides got off to an eventful start when Ryan Koolwijk opened the scoring for Dordrecht in the third minute.
Ernie Brandts' men held out for more than an hour thereafter, but Koolwijk then went from hero to villain when he was penalised for handball in the Dordrecht area, giving Oussama Tannane the opportunity to convert a 72nd-minute penalty.
Heracles, who had won their previous three matches, edge further clear of the bottom three as a result, while Dordrecht can at least take heart from claiming only their sixth point of the campaign.
Dordrecht had fortune on their side as they claimed a surprise lead. Koolwijk burst into the area before trying his luck with a cross-shot that beat Dennis Telgenkamp with the aid of a deflection.
Iliass Bel Hassani spurned a chance to immediately pull Heracles level and there was another setback for the hosts before the interval when captain Mark-Jan Fledderus was forced off with an injury.
However, the hosts eventually rescued a share of the spoils through Tassane, who converted from 12 yards after Bel Hassani had kicked the ball against the arm of Koolwijk.
