Goals by Derk Boerrigter and Kolbeinn Sigthorsson guided Ajax one step closer to the title as victory over FC Groningen kept them six points clear at the top of the Eredivisie.
Boerrigter put Frank de Boer's side at the end of a first half bereft of clear-cut opportunities with Sigthorsson securing the win 10 minutes from time.
Christian Eriksen shot narrowly wide after five minutes but the remainder of the half was barren in terms of goalscoring chances although the hosts dominated possession.
Ajax almost broke the deadlock three minutes before the break when Eriksen's first shot was thwarted by goalkeeper Luciano and although he was quick to pounce on the rebound, Lorenzo Burnet cleared the ball off the line.
The half was coming to an end when the hosts did manage to take an injury-time lead.
Siem de Jong's shot came to Boerrigter who slotted home into the left-hand corner.
Luciano prevented Ajax from doubling their lead when he kept out Theo Janssen's driven free-kick down to his left and moments later Boerrigter lobbed the keeper but the ball also cleared the bar.
Ismail Aissati then tried his luck with an individual run and shot which was deflected by Jonas Ivens on to the post and out for a corner.
Boerrigter shot wide before Sigthorsson gave Ajax breathing space in the 80th minute, guiding home a ball from De Jong.