Livingston is ahead 2-0 before the second leg of their William Hill Premiership play-off semi-final game against Partick Thistle at Firhill.
The Lions scored against the flow of the game to take the lead when Scott Pittman scored the first goal, six minutes before half-time.
Danny Wilson doubled their lead seven minutes into the second half, putting the Jags in a tough position for their upcoming match in West Lothian on Friday evening.
David Martindale’s team had a 10-day break before coming back to play in Glasgow, while Thistle played their third game in a week.
Livingston looked more energetic in the beginning, with Cristian Montano's first attempt saved by David Mitchell, and Dan O’Reilly clearing the rebound from the Colombian's shot off the goal line.
Partick recorded their first shot in the 24th minute, with Logan Chalmers shooting straight into Jerome Prior's arms.
Three minutes later, Brian Graham missed a great chance after failing to score from close range following a tackle from Robbie Crawford to outplay Jamie Brandon.
Thistle gained confidence as Crawford's shot narrowly missed the target on the half-hour mark, with the Livi goalkeeper struggling to reach it.
However, Livingston dealt a blow to the home team with a goal six minutes before half-time.
Montano passed to Robbie Fraser on the left and his pass found Pittman, who scored at the near post.
Partick almost conceded another goal just before half-time when Jamie Low's header didn’t reach Mitchell and was intercepted by Montano.
Fortunately for Low, his goalkeeper blocked Montano's shot, and Lee Ashcroft cleared Stephen Kelly's attempt.
Partick made a substitution at half-time, with Alex Jakubiak coming on for the injured Luke McBeth — but it was Livingston who was stronger in the game.
There were chances for Montano and Wilson before Wilson scored the second goal in the 52nd minute.
Kelly's free-kick was deflected to Wilson, who scored off the crossbar.
Livingston had all the momentum, aiming to secure the victory.
In the 54th minute, Mitchell made an important save to stop Pittman from scoring another goal.
Thistle searched for a comeback as Graham headed over a corner from Low.
Livingston continued to threaten, with Kelly's shot narrowly missing the goal in the 75th minute.
With eight minutes left, Ashcroft hit the crossbar with a powerful shot after a strong run forward.
In added time, Graham missed a good chance to score, leaving Thistle with a difficult task ahead to keep their promotion hopes alive.