By James Pearson
Last Updated: 01/01/70 1:00am
Holland international midfielder Rafael van der Vaart opened the scoring just after the hour mark, however Glen Salmon brought Groningen level.
With Ajax set to drop two points, defender Johnny Heitinga popped up and nicked a last-minute winner for the league leaders.
Feyenoord moved to within a point of second place PSV Eindhoven following a 3-0 success over NAC Breda at the FujiFilm-Stadion.
Belgian international Thomas Buffel was the hero for the Rotterdam side as he netted twice in the victory, with Peter van den Berg also getting his name on the scoresheet.
After a goalless first half, van den Berg opened the scoring after 52 minutes before Buffel's brace put the visitors in control.
The only blot on the fixture for Feyenoord was the dismissal of South Korean international Song Chong-gug, who saw red for picking up his second yellow card after 75 minutes.
Swedish international striker Johan Elmander, who is on loan to NAC from Feyenoord, was disappointing in his performance against the club that will be allowing him to depart De Kuip in the summer.
Utrecht climbed to sixth in the table after emerging victorious from an eight-goal thriller against ADO Den Haag at Nieuw Galgewaard.
The visitors were ahead just two minutes in after Youssef El Akchaoui netted, however Patrick Zwaanswijk restored parity three minutes later.
Roy Stroeve restored Den Haag's lead after 16 minutes but again the side failed to hold their advantage, with Dave van den Bergh equalised shorty after.
Zwaanswijk's second of the game put the home team ahead for the first time, but the visitors responded when Romeo Castelen squared the match at 3-3.
Utrecht controlled the second half and edged ahead just after the hour mark when van den Bergh scored his second of the game.
Donny de Groot got in on the action after 71 minutes to seal the 5-3 win before Regillio Simons was shown the red card for violent conduct.
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