Ajax can clinch its 31st league title with a victory at Steve McClaren's FC Twente on a Super Sunday for the Eredivisie.
Both matches kick off at the same time on Sunday.
Ajax moved within touching distance of the title with a 2-0 victory over FC Groningen last weekend which stretched its winning run to 11 games.
"We have one hand on the title. The important thing now is to put the other hand on it as well," De Boer said.
"We are not completely there yet, but things are looking good for us. We are almost there."
But Ajax can be sure that Sunday's game will be no title-winning stroll, with Twente one of five teams jostling for Champions League qualification.
Feyenoord and AZ are both on 61 points, six behind Ajax, while Twente and PSV Eindhoven have 60 and Heerenveen is also still in the hunt with 58.
Even if Ajax does wrap up the title this weekend, the race for European football next season is set to go to the wire.
PSV travels to Roda JC on Sunday while Heerenveen will look to improve on last week's 1-1 draw with Vitesse Arnhem when it travels to mid-table Heracles Almelo.
NEC Nijmegen and RKC Waalwijk meet on Saturday knowing defeat will effectively end their hopes of a place in the Europa League play-offs.
The battle to avoid automatic relegation is just as tight.
De Graafschap travels to Groningen with the opportunity to open up a four-point gap over bottom club Excelsior, which is in action on Saturday at Vitesse.
NAC Breda can secure its top flight status if it achieves a result at FC Utrecht that is better than what VVV-Venlo can manage at home to ADO Den Haag.