With PSV Eindhoven running away with matters in the Dutch top flight, this competition represents both sides' best chance of silverware this season.
Match preview
All things considered, Feyenoord can be satisfied with the current defence of their Eredivisie title, a total of 46 points from 20 matches being an excellent return.
Nevertheless, there will be disappointment that they sit 10 points adrift of PSV, not helped by recent draws against NEC Nijmegen and Twente respectively.
A 1-0 win over AZ in a league fixture on away territory on Sunday has boosted the chances of Arne Slot's side at a time when PSV were held by Ajax.
That said, Feyenoord find themselves needing to kick-start their campaign, and their hope is to take advantage of being the biggest team left in this competition.
Feyenoord overcame PSV in the last 16, running out 1-0 victors over their domestic rivals, in a tie which followed a 2-1 success over FC Utrecht in the previous round.
From the perspective of AZ, they are in desperate need of getting back on track having gone five matches without success in the Eredivisie.
Losing to Feyenoord at the weekend has left Maarten Martens's team level on points with a resurgence Ajax and at risk of dropping down to fifth position.
Although their fixture list eases somewhat after this contest, Martens's knows that he needs a standout victory to justify his recent appointment.
AZ have been far from convincing against lower-level teams in this competition, first requiring extra time to win 3-2 at HHC before they edged out Quick Boys in a penalty shootout in the last 16 after a 3-3 draw.
Feyenoord KNVB Beker form:
W
W
Feyenoord form (all competitions):
L
D
W
W
D
W
AZ Alkmaar KNVB Beker form:
W
W
AZ Alkmaar form (all competitions):
D
L
W
D
D
L
Team News
With goalkeeper Justin Bijlow suffering an injury in the first half of the game on Sunday, Timon Wellenreuther should replace him between the sticks for Feyenoord.
Bart Nieuwkoop and Yankuba Minteh could also be handed chances on the flanks, but Slot may be prepared to stick with the remainder of the previous starting lineup.
Martens could also make alterations in wide areas for AZ with Ernest Poku and Ibrahim Sadiq both pushing for opportunities from the start.
Kristijan Belic may also make just his second start in midfield after recently arriving from Partizan Belgrade.
Like with his opposite number, though, Martens will keep changes to a minimum given their chances of winning this competition if they can progress.
Feyenoord possible starting lineup:
Wellenreuther; Geertruida, Trauner, Hancko, Hartman; Wieffer, Timber, Zerrouki; Nieuwkoop, Gimenez, Minteh
AZ Alkmaar possible starting lineup:
Owuso-Oduro; Penetra, Goes, Bazoer, Wolfe; Clasie, Mijnans, De Wit; Poku, Pavlidis, Sadiq
We say: Feyenoord 3-1 AZ Alkmaar
Although AZ are managing to cling onto fourth spot in the league, their recent form has been poor. With that in mind, we can only predict a convincing home victory, even if Slot does decide to make a couple of alterations.