Fernandez (pictured) opened the scoring for newcomers Excelsior after 29 minutes on the counter-attack but defender Ron Vlaar equalised before the interval and an own goal from Excelsior's Miquel Nelom with 16 minutes remaining put Feyenoord on track.
Daan Bovenberg, however, headed home an equaliser for Excelsior before Fernandez made the most of sloppy defending by Andre Bahia to seal the win three minutes into stoppage time when he first hit the post and then netted the rebound.
PSV Eindhoven are top with six points from two matches after a 6-0 win over Graafschap Doetinchem on Saturday. Behind them on on goal difference are NEC Nijmegen, who beat Willem II Tilburg 5-3 with Bjorn Vleminckx scoring a hat-trick.
Ajax Amsterdam, who beat Vitesse Arnhem 4-2 on Saturday, are third with four points, with Roda JC Kerkrade, 3-1 winners at ADO Den Haag, on the same points.
Utrecht striker Ricky van Wolfswinkel, who won his first Netherlands cap on Wednesday in a friendly against Ukraine, hit a double to earn his team a 3-1 home win over NAC Breda.
Champions Twente Enschede are 14th in the league with two points as the 0-0 home draw against Heerenveen keeps them winless and goalless.
