Thistle don't add to their first half goals but it is a dominant Thistle performance across the 90 minutes. 

Into the quarter-final we go with a bounce and boing. 

Minimum of three minutes added time to be played. 

Man of the Match: Ts'oanelo Lets'osa. 

A standing ovation for the Thistle number 64. 

Another stop from Mitchell, this time to deny Stanway. 

An Ure cross lands on the roof of the Thistle net. 

A flutter of anxiety for Thistle but a deflected shot ends up in the arms of Clarke. 

Appeals for a Thistle penalty as Reading is challenged inside the box

Crowd: 3,124.

Crawford is caught by the already booked Ure. Thistle have free kick midway inside the Ayr half on the right. 

Thistle are so close to a third as Fitzpatrick slips the ball past Mitchell but also just wide of the keeper's far post. 

McAllister gets his head to a free kick deep into the Thistle box but his header doesn't really threaten the Thistle. 

Ayr clear the corner but Thistle have a throw down by the corner flag. 

Watt denied, not for the first time, by Mitchell. 

The flag goes up for offside as Thistle treey and make something of the free kick. 

Watt is bundled over and Thistle have a free kick near the left corner flag. 

Ure's late challenge on Lets'osa earns him a yellow card. Lets'osa was simply too quick for him. 

Fitzpatrick gets his shot from outside the box all wrong but Thistle have made a good start in general to the second half. 

Reading has an opportunity at the edge of the box but his right foot effort doesn't have enough curl on it to trouble Mitchell. 

Fitzpatrick takes the corner short to Lets'osa who sees his ball into the box cleared. 

Watt pushes a pass to Chalmers to his right. Chalmers has room for a shot from the edge of the box but his effort is too high. 

Ayr make a change at the break. 

The goals came late in the half but Thistle's two goal lead is a richly deserved one at the end of a largely one-sides first 45 minutes. 

Job only half done though. 

Mitchell can only just stand and watch as Chalmers' low drive from outside the box deflects off of Tony Watt's leg and finds the bottom corner of the net. 

Well, we knew it was going to happen didn't we?

Into added time at the end of the first half. 

Chalmers again goes deep with his corner but this time can't find O'Reilly and the ball drifts out for a goal kick. 

Nearly a second but Mitchell pushes away Watt's shot. 

A richly deserved opener for Thistle. Chalmers' corner finds Dan O'Reilly at the back post and his header loops into the opposite corner of the net. 

A last ditch tackle denies Watt but earns Thistle a corner. 

Mitchell makes an excellent one handed save low to his right to deny Chalmers who is set up by McPherson's cross. 

Lets'osa does well to find Chalmers to his right. Chalmers sees his cross scrambled clear. 

Lets'osa breezes past a couple of challenges near the edge of the Ayr box. He finds Watt with a pass. watt though can't quite get the ball from under his feet and when he does stab a shot towards goal Mitchell is there to save. 

A confident catch from Clarke removes that threat. 

The corner is flicked away from goal but Ayr win a free kick wide on the left to maintain a threat to the Thistle goal. 

Both Crawford and Stanway see shots blocked as Thistle press for the opener. 

Mitchell comes off his line to claim a Chalmers cross ahead of Crawford who had made a late run into the box. 

The ball is in the Ayr net when Fitzpatrick fires home after Mitchell claws away a Watt header that looked as if it might have crossed the line. The flag is up for offside against Fitzpatrick so Thistle are unlucky on two fronts. 

Thistle, and Fitzpatrick, are so close to scoring. Watt's header finds Fitzpatrick near the halfway line and he has too much pace for his marker. He has the option to find Lets'osa to his right but goes for goal himself and his shot smacks off the post. The ball breaks to Chalmers but he slices his shot away from goal and the ball is knocked behind for a corner. 

Some excellent link up play from McPherson and Chalmers sees Chalmers progress deep into the Ayr box but he can neither fashion a shot or as cross. 

Chalmers again involved and once again Mitchell gathers the low cross that comes in. 

Thistle don't go direct towards the box from the free kick and are forced back. Chalmers though picks the ball up from McPherson and finds Lets'osa who drills in a low cross that Mitchell gathers. 

Watt is fouled and Thistle win a free kick inside the Ayr half. 

Kick-off is now just a little over 20 minutes away with a place in the quarter-final of the Premier Sports Cup up for grabs for both Thistle and Ayr United. 

Head Coach Mark Wilson has made two changes to his starting eleven from the side that started last weekend. 

In come Ben McPherson and Ts'oanelo Lets'osa. 

Cammy Logan and Luke McBeth are the two that drop to the bench where they are joined, among others, by new signing Alex Samuel. 

There are some familiar faces in the shape of Stuart Bannigan and David Mitxchell in the Ayr United starting eleven.