Title-chasing Ajax came from behind at half-time to see off Eredivise basement boys Willem II after the strugglers had Denis Halilovic sent off.
Rangelo Janga put the hosts ahead in the 19th minute before Siem de Jong levelled matters just after the restart.
With the scores locked at 1-1, Halilovic was dismissed before Jan Vertonghen and Christian Eriksen scored in the 80th and 88th minutes to win it for the visitors.
Willem started positively, Jeroen Verhoeven saving well from Ricardo Ippel after good work by Maceo Rigters.
Eriksen returned fire for Ajax with 14 minutes gone but Vladan Kujovic was up to the challenge in the home goal.
The goal came following an error from Ajax defender Toby Alderweireld whose sloppy clearance allowed Juha Hakola to feed Janga.
He rounded Verhoeven before slotting home into an empty net.
Demy de Zeeuw had two good chances for Ajax before half-time but missed with both.
De Jong equalised with the first real attack of the second half, curling his shot clinically into the bottom corner.
Ajax initially failed to capitalise but their chances rocketed when Halilovic scythed down Vertonghen and received his marching orders in the 73rd minute.
Vertonghen made Willem pay with 10 minutes remaining, lashing home Ajax's second from 25 yards before Eriksen added the icing on the cake with a neat chip over Kujovic in the closing moments.