Ajax beat Heracles 4-0 at the Amsterdam ArenA while NEC drew 1-1 at home to AZ in Sunday's Eredivisie action.
Lasse Schone started the scoring after 13 minutes for Ajax and it took until seven minutes after the break for Kolbeinn Sigthorsson to add a second.
Ajax could even afford to have Kenneth Vermeer sent off after 48 minutes as substitute Ryan Babel added a third with 15 minutes left.
The home side saved the best for last as Christian Eriksen's spectacular curling third in the closing minutes sealed the win.
Utrecht jumped above Heerenveen and into sixth after Jens Toornstra netted in the 71st minute against ADO Den Haag, while Heerenveen lost 3-1 at FC Groningen.
The visitors made the worst possible start when Jukka Raitala put through his own net after three minutes before a Leandro Bacuna spot-kick three minutes before the break extended their advantage.
Lukas Marecek pulled a goal back in the 70th minute but Michael De Leeuw sealed the win with three minutes left.
AZ are four points clear of the relegation zone after a 1-1 draw at NEC.
Adam Maher put the visiting side a goal up after 17 minutes but just two minutes later the hosts were level through Kevin Conboy.
Nick Van der Velden saw red for the home side after 61 minutes, but AZ could not force a winner.