Thistle will take an important three goal advantage into next Friday's second leg at Somerset Park. 

Job not done yet but Thistle couldn't really have hoped for a better position albeit they could have won by more than three after a slow start. 

Thistle break and Mullen tests Albinson with a powerful shot. There will be no time for the corner. 

Bryden takes the free kick and hits the bar. 

Ayr win a free kick on the very edge of the Thistle box in a central position. 

Docherty clears Smith's corner. 

The referee finally stops play after Docherty takes a knock clearing the ball inside the Thistle box. 

Mitchell makes a fantastic one handed save low to his left to keep out Dempsey's shot from 8 yards out. 

Man of the Match: Scott Tiffoney

McKinnon crosses from the right but Mullen rather swipes at his attempt to meet the cross. 

Mitchell is down sharply inside his six yard box to save a low shot. 

Dowds sends a low cross into the box that isn't too far ahead of MacKenzie. 

Mitchell gets a hand to a dangerous Smith corner. 

Aye can't handle Lawless and he gets to the bye line but can't find a team mate with his cut back. 

Ashford tries to squeeze the ball home from a tight angle but there are too many Thistle bodies between him and the Thistle goal. 

A huge goal in the context of the tie. A It's a simply executed one Fitzpatrick crosses from the left and Graham has time and space to fire home. 

Docherty clears a header from close to the Thistle goal line. 

Ayr enjoying a spell of possession. You do feel that the next goal in this tie could be huge. 

Crowd: 7,012

Dempsey clatters Tiffoney and earns himself a yellow card. 

Mitchell punches the free kick clear accidentally catching McAllister in the process. The Ayr sub looks okay and play restarts with an Ayr throw. 

Ayr win a free kick wide on the left in line with the edge of the Thistle penalty box. 

McAllister crosses from the right for Ayr but O'Connor isn't able to get his foot round the ball to threaten the Thistle goal with his shot. 

Thistle miss a glorious opportunity for a third. Tiffoney sets up Fitzpatrick but he shoots over the bar. Firhill is bouncing right now. 

A Fitzatrick cross is cleared only as far as Turner at the edge of the box but his shot is a tame one that doesn't threaten the Ayr goal. 

He might have missed a good chance in the first half but Brian Graham wasn't going to pass up a second opportunity. Docherty finds Tiffoney inside the box and his cross is tucked home by Graham at the back post. 

And are a whisker away from a second goal with a Fitzpatrick effort from the edge of the box clipping the top of the crossbar. 

Brownlie's header from Turner's corner is blocked. Thistle remain on the attack. 

Some shouts for a handball and a Thistle penalty following Turner's corner but they were highly optimistic. 

Thistle on the front foot early in the second half. 

After a bit of an unscheduled delay Thistle get the second half underway. 

Thistle lead at the break through Jack McMillan's goal. 

The goal itself came against the run of pay but since the opener Thistle have had chances to extend their advantage while Ayr remain a threat. 

A Mullin shot is blocked by Holt. 

Mullin's free kick goes all the way through to Mitchell. 

Ayr free kick deep inside the Thistle half. 

Lawless lifts a beautiful cross to the back post where it finds the head of Graham but his header drops agonisingly wide of goal. 

An odd little passage of play finishes with Docherty lifting a shot from outside the box a yard so over the Ayr crossbar. 

Albinson whips the ball away from Docherty after a mistake in the Ayr defence. 

Chance for Ayr. McKenzie spins away from his marker before finding O'Connor to his left. O'Connor crosses but Mullin can't get the ball on target. 

Fitzpatrick knocks a pass forward to Tiffoney but Tiffoney doesn't time his run and is caught offside. 

A run deep into the Ayr box from Turner is halted by the foot of Musonda. 

Fitzpatrick gets the better of the Ayr full back and whips over a cross that Graham looks as if all he has to do is touch to put Thistle two up but he sends the ball wide. 

McGinty nods Mullin's deep corner back towards the Thistle goal. Dempsey tries to turn and shoot but his effort spins away from the Thistle goal. 

Cheap corner conceded by Thistle. 

Turner's corner is cleared and Ayr break. O'Connor's progress though is halted by McMillan. 

Graham knocks the ball out wide to Tiffoney who sees his cross cleared. 

Tiffoney picks the ball up after Brownlie flicks the corner on but he is quickly closed down by two defenders and any threat is cleared. 

Ayr are unconvincing in clearing Turner's free kick and Thistle remain in a threatening position wide on the other flank. Lawless drills in a low cross that is well cleared. 

Holt is caught earning Thistle a free kick in from the left touchline midway inside the Ayr half. 

Chance for a second. Albinson makes a mess of dealing with a long ball forward from Muirhead. The ball falls to Graham who can't lift the ball towards the unguarded net. 

Lawless takes the corner but it is an easy take for Albinson inside his 6 yard box. 

Against the run of play Thistle take the lead. It's a gem of  a pass from Lawless that finds McMillan deep inside the box and from a tight angle he buries the ball past Albinson and into the back of the net. 

Thistle haven't, or haven't been allowed to, settle yet. Despite that Tiffoney chance it has been Ayr that have been the better side. 

Ayr work a short corner and when the ball comes back to Mullin he overhits his cross and the ball goes out for a goal kick. 

Thistle break and they nearly take the lead with Albinson making a good stop to his right to deny Tiffoney. 

Thistle are careless in possession and put themselves under pressure before they eventually clear. 

There's almost a chance for Musonda at the back post as Ayr threaten from the corner but his flicked effort drifts away from goal.  

Mitchell gets a fingertip to Maguire's drive from outside the box. 

It's a poor free kick from Mullin though and the ball drifts out for a goal kick at the far post. 

Ayr win a free kick in from the left touchline following a foul on Murdoch. Chance to test the Thistle defence. 

Turner's corner is just a shade too high for either Brownlie or Graham who both stretch their neck muscles trying to reach it. 

First burst of pace from Fitzpatrick earns Thistle their first corner. 

Mitchell is off his line quick to collect the ball and immediately launches the ball upfield trying to find Tiffoney but the ball runs away from Tiffoney despite his best attempts to reach it. 

Mitchell tips a header over his crossbar but the flag had already gone up for offside. 

Ayr kick the game off. Thistle shooting towards the John Lambie Stand in the first half. 

With kick-off now just under 15 minutes away the nerves are starting to jangle in proportion to the building of the atmosphere. 

For this Play-off Semi-Final First Leg, Kris Doolan has selected the same side that was so impressive in seeing off Queen's Park last Friday setting up tonight's eagerly anticipated fixture.