League One leaders Raith Rovers return to winning ways with a 2-1 victory over Forfar at Stark's Park.
The top three in Scottish League One all lose, allowing fourth-placed East Fife to close the gap on first to four points after they beat Forfar.
Airdrieonians boost their promotion hopes in Scottish League One as they beat Clyde 2-0 at home for a first win in six matches.
Raith Rovers beat Montrose 4-3 to stay one point ahead at the top of Scottish League One as second-top Falkirk hammer Forfar Athletic 6-0.
Scottish League One
Audio & Video
Daniel Stendel earns his first win as Hearts manager as his side scored five times against League One Airdrieonians to reach the last 16 of the Scottish Cup.