AZ's hopes of a domestic double came to an end when they suffered a shock defeat to Heracles Almelo in the semi-finals of the KNVB Beker.
AZ saw their lead at the top of the Eredivisie table cut to a point by Ajax at the weekend, but looked on course to bounce back when they led 2-1 against a visiting side who came into the game on the back of four straight defeats.
However, Heracles had other ideas and equalised to force extra time, where they scored twice more to complete a stunning upset.
The visitors took the lead with seven minutes gone after forcing three corners in succession, eventually finding the net when Willie Overtoom's cross from the left was headed home by Everton.
AZ then saw Maarten Martens curl a free-kick over the bar before equalising in the 20th minute as Adam Maher turned in Simon Poulsen's cross via the left-hand post.
And just two minutes later the home side were in front as Johan Gudmundsson picked the ball up just outside the area and drove into the box before firing a shot past Dennis Telgenkamp.
Chances were harder to come by after that, but Heracles got back on level terms after 65 minutes when Kwame Quansah headed home from six yards out following Lerin Duarte's cross.
Telgenkamp then had to save from Charlison Benschop and Brett Holman as the visitors held on to force extra time, and it was they who made the most of the extra 30 minutes.
With 110 minutes on the clock, substitute Thomas Bruns rattled home a powerful shot just four minutes after coming on, while Ninos Gouriye made certain of his side's first appearance in the final with a fourth in the last minute.