A goal inside five minutes from Darryl McHardy and a brace from Jamie Reid saw Elgin City inflict a surprise 3-0 defeat on Scottish League Two leaders Albion Rovers.
Albion, who had won their last five league games, remain top but have had their lead cut to six points after Queen's Park drew 1-1 with Berwick Rangers.
Third-placed Arbroath also suffered a shock defeat at Ochilview Park as Kevin Nesbit's goal was enough to give East Stirlingshire a 1-0 win.
The big winners at the top were East Fife, who consolidated their place in the final playoff spot as a brace from Nathan Austin and an own goal from Jonathan Crawford gave the Fifers a 3-0 win over bottom-placed Montrose.
Elsewhere, Clyde moved a step closer to safety as Jamie Pollock's late goal gave them a 1-0 victory over Annan Athletic.
Results in full: Albion Rovers 0-3 Elgin City, Annan Athletic 0-1 Clyde, Berwick Rangers 1-1 Queen's Park, East Fife 3-0 Montrose, East Stirlingshire 1-0 Arbroath.
Joe Sharratt
