Leaders FC Twente saw their perfect start to the new Eredivisie season come to a crashing halt as they slumped to a 1-0 defeat at Ajax.
Twente had won all six of their league matches prior to today but saw their lead at the top of the standings trimmed as Christian Eriksen struck the only goal for Ajax in the 68th minute.
Ajax's win saw them close to within three points of their beaten opponents, while second-placed Vitesse Arnhem also profited as they moved to within a point of the summit with a 2-1 win at FC Utrecht.
The visitors took the lead through Marco van Ginkel in the 55th minute and Wilfried Bony made it 2-0 just five minutes later.
Substitute Jacob Mulenga pulled one back for Utrecht in the 71st minute but unbeaten Vitesse held on for their fifth win in seven league outings this season.
Feyenoord are fourth, two points shy of Ajax, after a 5-1 thumping of NEC Nijmegen.
Lex Immers struck a hat-trick for the victors, tucking home a 47th-minute penalty before adding further strikes in the 63rd and 85th minutes.
Graziano Pelle (16, 44) scored a brace for Feyenoord, while NEC replied through Soren Rieks four minutes into the second half.
ADO Den Haag remained in seventh place after a battling 3-3 draw at Heracles Almelo.
Lerin Duarte's own goal handed ADO a 12th-minute lead that kicked off a crazy spell of three penalties and five goals in just 20 minutes.
Willy Overtoom levelled from the spot for the hosts eight minutes later, but four minutes after that ADO had a spot-kick of their own that Danny Holla tucked away.
The referee pointed to the spot again in the 29th minute to allow Overtoom to pull Heracles level for the second time, while the hosts went in front in the 32nd minute when Ninos Gouriye fired home.
The excitement died down after that breathless passage of play, but there was still a twist to come as Holla popped up with his second in the 73rd minute to ensure it finished all even.
In the day's final game, Heerenveen picked up their first win of the season with a 2-0 victory over NAC Breda, Alfred Finnbogason (nine) and Daniel De Ridder (40) with the goals.