Anthony Andreu's first-half strike ensured Livingston returned to winning ways with a narrow victory over third-placed Dunfermline.
Andreu saw his 18-yard shot tipped round the post by Paul Gallacher in the 11th minute, but he went one better nine minutes later.
The midfielder scored the winner for the Lions, who lost to leaders Morton last time out, when he was on hand to convert Marc McNulty's cross from close range.
Dunfermline had a chance to level late on, but substitute Ryan Thomson missed the target from 18 yards and Shaun Byrne saw an effort blocked by defender Jesus Garcia Tena.
John Potter fluffed his lines and failed to test Andrew McNeil as Livingston held on for a vital three points.
Dunfermline: Gallacher, McMillan, Dowie, Potter, Jordan, Falkingham, Geggan (Thomson 23), Byrne, Cardle, Wallace (Dargo 59), Kirk. Subs Not Used: Hrivnak, Whittle, Kane.
Livingston: McNeil, Kyle Jacobs (Booth 89),Garcia Tena, Barr, McCann, Andreu (Morton 67), O'Brien, Fox, McNulty, Scougall, Iain Russell (Mullen 74). Subs Not Used: Jamieson, Fordyce.
Booked: Garcia Tena, Iain Russell, Kyle Jacobs.
Goals: Andreu 21.
Ref: Mike Tumilty