Having seen Peter Bosz depart for Maccabi Tel Aviv during the winter break, Arnhem responded with victory at the Cambuur Stadion thanks to second-half goals from Milot Rashica and Valeri Qazaishvili.
Zwolle impressed on their return from the winter break by defeating 10-man Heerenveen 5-2.
The hosts boasted a two-goal half-time cushion thanks to Dirk Marcellis and Bram Van Polen, but Mitchell Te Vrede reduced the deficit in the 47th minute.
However, Joey van den Berg's sending off shortly afterwards left Heerenveen struggling, with Van Polen scoring a penalty before Wout Brama and Stefan Nijland netted either side of Jerry St Juste's consolation goal.
AZ moved up to 10th after a 1-0 win at Roda JC.
Vincent Janssen's sixth-minute goal proved decisive as not even Derrick Luckassen's sending off early in the second half proved enough to help turn the tide.
Rostyn Griffiths started for Roda but was replaced after 68 minutes, while Daniel De Silva came on as a substitute with six minutes remaining.
Meanwhile, De Graafschap left it until late to secure a 2-0 win against Excelsior, with Cas Peter's second-half goal followed up in injury-time by Vincent Vermeij.