Slovenian striker Tim Matavz put PSV ahead after 90 seconds, while Ajax left-back Nicolai Boilesen was carried off on a stretcher after 18 minutes with a hamstring injury.
PSV goalkeeper Przemyslaw Tyton also left the pitch on a stretcher with concussion after a collision with team mate Timothy Derijck after 30 minutes.
Kolbeinn Sigthorsson (pictured) equalised for Ajax four minutes into first-half injury time and the visitors came close to taking the lead when Derk Boerrigter hit the side netting seconds later.
PSV restored the lead 10 minutes into the second half when Georginio Wijnaldum converted a penalty but with 11 minutes remaining Dmitri Bulykin salvaged a point from close-range after sloppy defensive work from Erik Pieters.
Twente Enschede cruised to a 5-2 home win over ADO Den Haag to move top with 15 points after six matches, ahead on goal difference of AZ Alkmaar, 2-1 winners at RKC Waalwijk, with Rasmus Elm and Charlison Benschop on target.
Ajax are third with 14 points, ahead on goals scored of Feyenoord, who beat Graafschap Doetinchem 4-0 on Saturday. PSV remain fifth with 11.
Ajax host Twente next Saturday, while Feyenoord travel to Alkmaar a day later.
