That's all from me. Good night.
You can watch highlights of Livingston v Partick Thistle on Sportscene on BBC Two Scotland and BBC iPlayer from 23:15.
Before then, of course, it's the Scottish Cup final on Saturday - available on BBC One Scotland, Radio Scotland and the BBC Sport website.
The Premiership play-off final will be decided on Sunday when the second leg takes place at Firhill.
We will be covering that match here on the BBC Sport website and on Sportsound on BBC Radio Scotland.
Partick Thistle manager Alan Archibald: "I didn't think we played at all.
"We got drawn into playing long, aimless balls up front to our two strikers, which is something we've not done when we've played that kind of system and that shape recently so that was disappointing.
"The goal probably overshadowed what a bad start we had.
"We've got to get more efforts on goal, we've got to score goals, obviously, to get back into the tie.
"We're fighting for our lives, they're trying to take our place, we've got to make sure we're ready for that."Copyright: SNS
Livingston manager David Hopkin: "It's only half-time. I just wish the games were played over one leg.
"Our squad's down to the bare bones and the players give me everything.
"Tonight, to win 2-1 at home, it's great to finish the season at home with a win. I thought they were fantastic.
"We score a fantastic equaliser. At half-time, I keep saying, if it had finished at 1-1, I'd have been delighted.
"Josh Mullin's gone and put a fantastic ball in and then Scott Pittman, what a finish it is to go near post.
"The biggest thing about us now is recovery. We've only got 15 fit players now. It's about patching players up.
"We know it's going to be a hard shift on Sunday. I'm so proud of every player. We just keep going and we just keep defying the odds."Copyright: SNS
Livingston striker Lee Miller tells BBC Scotland: "It was a great shift from the boys, to a man. Every game we fight for one another.
"We've got tremendous character. People who will run that extra yard for each other, make a bad ball a good ball. We're doing things right and we'll see what happens on Sunday.
"My foot is in bits. My ankle is sore, my eye is sore. We're all warriors out there and we'll go again."
BBC Sport Scotland
Livingston will be delighted with the result but more so the performance. They were better than Thistle throughout this contest.
David Hopkin’s side now have all the momentum. The pressure is now firmly on Partick Thistle, whose Premeriship future is hanging by a thread.
They need a vastly improved display because it is unlikely that Livingston will fail to turn up on Sunday.Copyright: SNS
Livingston take a lead into Sunday's Premiership play-off final second leg.
David Hopkin's side trailed early on to Kris Doolan's header but levelled quickly through Keaghan Jacobs and Scott Pittman's strike has given them the advantage and the initiative at the midway stage of the tie.Copyright: SNS
Three minutes of injury time begin.
BBC Sportsound summariserQuote Message: Partick Thistle don't seem to be up for it. There's no leaders trying to galvanise them. They almost seem happy at 2-1.Copyright: SNS
Lee Miller comes off for Livingston and on comes Gregor Buchanan.
Baily Cargill goes down in the Livingston box as he tries to get on the end of Adam Barton's cross. Referee Craig Thomson takes no action.
Miles Storey replaces Conor Sammon for Partick Thistle.
Scott Pittman's shot is turned out by goalkeeper Tomas Cerny. Fine save, but an offside flag had been raised against Pittman.
A bit of pressure from Partick Thistle as they send a high ball into the box but Conor Sammon is beaten to the cross by goalkeeper Neil Alexander's glove.
BBC Scotland summariserQuote Message: Partick Thistle are in serious trouble here. They have not played well tonight. It is no more than Livingston deserve, they have been by far the better team, and Partick Thistle should count themselves lucky they are not more than 2-1 down.
BBC Sport Scotland
Livingston’s second is fully deserved and was the result of a wonderful move.
Scott Pittman takes the credit for a lung-bursting run that he finished emphatically but it was a very good team goal.
Alan Archibald must be deeply concerned at this. His side is deservedly behind and all the positive energy right now is with David Hopkin’s side.
They must fancy their chances of promotion now and could go in for the kill in these final stages.
Scott Robinson is withdrawn as Livingston introduce Nicky Cadden.
He scored in the semi-final and Scott Pittman's put Livingston in front in this tie for the first time.
Substitute Josh Mullin gets to the byline and pulls back for Pittman to convert from close range.Copyright: SNS