Eredivisie leaders PSV Eindhoven were stunned by Heerenveen in a 2-1 loss on Saturday.
PSV – who could have gone five points clear of title rivals Ajax with victory – slumped to the defeat in front of almost 25,000 fans at the Abe Lenstra Stadion in Heerenveen.
Marco van Basten's side were in dreadful form earlier in the season but they have now posted three wins in a row, a run which has seen them rise to ninth on the table.
The winners took the lead after just eight minutes when Belgian Yassine El Ghanassy supplied an assist for Marten de Roon.
And El Ghanassy's involvement in crucial moments continued seven minutes before half-time, when he netted his side's second goal.
Midfielder Kevin Strootman pulled back a goal for PSV with 15 minutes to play but they ran out of time to grab an equaliser.
Ajax will have the chance to move to the top of the table when they take on PEC Zwolle on Sunday.
In other matches, AZ drew 1-1 with ADO Den Haag in Alkmaar. Mike van Duinen opened the scoring after 10 minutes for ADO Den Haag, but their advantage was cancelled out later in the first half. Viktor Elm was the scorer for AZ, who have now failed to win in six consecutive Eredivisie matches.
Bottom-placed Willem II moved within five points of the second-last VVV Venlo with a 1-0 win.
Substitute Danny Guijt scored the only goal of the game with just one minute of normal time remaining.
Heracles also won 1-0, defeating NEC Breda thanks to a second-half strike from Brazilian Everton.