Feyenoord moved into second place for the first time this season as they walloped Go Ahead Eagles 5-0, leapfrogging PSV Eindhoven and Vitesse Arnhem who both failed to win on Saturday.
Stefano Denswil headed home a freekick to give Ajax a first half lead, with victory secured in seven second-half minutes with further goals to Lasse Schone and Bojan Krkic.
"It would be really bad if we let it slip from here," Ajax coach Frank de Boer said after the match.
His side now have 62 points from 29 games, comfortably ahead of Feyenoord on 54, and meet RKC Waalwijk on Wednesday.
If they win that match and next weekend's clash with Vitesse they could secure a record-extending 33rd league title provided other results go their way.
Lex Immers put the Rotterdam side one goal ahead at the break at home to Go Ahead Eagles and four more goals in the second half proved Feyenoord could cope without suspended top scorer Graziano Pelle.
PSV suffered a surprise 3-2 defeat at home to Groningen on Saturday while Vitesse drew, with both now sitting on 53 points.
AZ Alkmaar, whose veteran coach Dick Advocaat announced on Saturday that he would not stay beyond the end of the season, were held to a 0-0 draw at SC Cambuur while ADO Den Haag came from behind to draw 1-1 at home with PEC Zwolle, who on Wednesday clinched a berth in the Dutch Cup final.
Romeo Castelen scored the only goal as RKC won away to condemn Roda JC Kerkrade to another week in last place.
RKC remain in relegation danger, third from bottom but are five points clear of Roda and three ahead of NEC Nijmegen, who lost at home on Saturday.
The bottom-placed team is automatically relegated with the next two above them going into a promotion-relegation play-off.
- Sports & Recreation
- Vitesse Arnhem
- Go Ahead Eagles
- PSV Eindhoven
- RKC Waalwijk