Substitute Nacer Chadli scored a late winner as FC Twente kept up the pressure on Eredivisie leader Ajax with a 1-0 win away to Excelsior Rotterdam.
With Ajax playing on Sunday afternoon (Monday morning AEST), Twente knew it needed a win to keep its title hopes alive.
It now lies four points behind Ajax after Chadli netted the only goal of the game late on.
A win would have put the home side second in the table but a point left it in fourth on goal difference behind AZ and Feyenoord who both play later this weekend.
Heerenveen had looked on course for the win after taking the lead five minutes into the game through
FC Utrecht ensured its Eredivisie safety with a hard-fought but deserved 2-0 victory at RKC Waalwijk.
The result left Utrecht only two points adrift of its ninth-placed host, which lost ground in its bid for a UEFA Europa League play-off place.
De Graafschap was condemned to at least a place in the relegation play-offs after losing 3-2 at home to nine-man Heracles Almelo.
The home side started the weekend second from bottom, 12 points behind 15th-placed NAC Breda, which lost at home to Roda JC the previous night, with four games to go.
Soufian El Hassnaoui opened the scoring before
Mark Looms was dismissed for a second yellow card but the nine men survived a tricky last five minutes.