Ajax beat PSV to maintain pressure on AZ
Alkmaar stayed top on 56 points, one point ahead of Ajax, after beating mid-table RKC Waalwijk 1-0 with Johann Gudmundsson scoring the winner four minutes into the second half.
Aissati opened the scoring for Ajax after 56 minutes with a brilliant long-range drive into the corner.
Six minutes later he was fouled by Marcelo resulting in a penalty which was converted by De Jong (pictured) to wrap up their seventh straight win.
Twente Enschede are third with 52 points after being held to a 1-1 draw by ADO Den Haag on Saturday.
PSV are on 51 points along with Feyenoord and Heerenveen who registered wins over Graafschap Doetinchem and VVV Venlo respectively.
John Guidetti, on loan from Manchester City, broke the deadlock for Feyenoord away at bottom side Graafschap 19 minutes before time with his 19th of the season before Ruben Schaken and Sekou Cisse settled the match with a second and third goal.
Cup finalist Heracles Almelo ended a four-match losing streak in the league with a 3-1 win over 10-men Utrecht with substitute Ninos Gouriye hitting a late double after Alje Schut was sent off.