Brian Graham struck a second-half double as Partick Thistle took a major step towards the cinch Premiership play-off final with a 3-0 first-leg victory over Ayr at Firhill.

Graham had other chances following Jack McMillan’s 16th-minute opener as a dominant Thistle continued their impressive form under Kris Doolan in front of a 7,012 crowd.

The Jags have now only lost once in 16 matches since their former striker succeeded Ian McCall and have netted 11 goals in the play-offs so far.

The 2,000 fans in the sold-out visiting section got a shock before kick-off when top goalscorer Dipo Akinyemi was missing from the team lists, apparently with a back injury.

The striker has played in every other game for Ayr this season and hit 24 goals.

Manager Lee Bullen brought in Mark McKenzie, whose fifth goal of the campaign sent Ayr into second place in the Championship in the final moments of the regular campaign at Inverness.

Ayr made a bright start and Chris Maguire saw his well-struck first-time effort from 25 yards acrobatically saved by David Mitchell.

Scott Tiffoney forced a decent stop from Charlie Albinson at the other end and Thistle got on top before taking the lead. Steven Lawless threaded a ball through for McMillan who had sneaked behind the home defence before rifling a shot through Charlie Albinson.

Thistle continued to dominate with their creative players producing some excellent touches, and they should have been further ahead by the break with Graham missing two open goals, although both times the ball flashed at him quickly.

The experienced striker volleyed the first chance wide from outside the box with Albinson stranded after coming out of his box to head a long ball up into the air. Graham then missed from close range following Aidan Fitzpatrick’s driven cross.

The striker, who hit his 50th Thistle goal in the quarter-finals, then saw a header drift wide.

Ayr rarely got forward in the first half following their early pressure but Josh Mullin had a couple of half-chances, heading over before having a shot blocked.

The Jags maintained their dominance after the interval. Fitzpatrick hit the bar from long range before Graham converted from close range in the 50th minute after Tiffoney had played the ball across the face of goal. There was a hint of offside but no flag came.

The hosts continued to create chances. Kyle Turner curled wide from 18 yards and Fitzpatrick blazed over from an excellent opportunity.

Ayr defender Frankie Musonda saw a header blocked in the goalmouth before Thistle patiently worked the ball forward on the break and extended their lead in the 72nd minute as Graham finished first time from six yards following Fitzpatrick’s curling delivery.

Ayr threatened to snatch a late lifeline. Mitchell got down well to make an excellent one-handed stop from Ben Dempsey before substitute Paul Smith hit the bar with a 20-yard free-kick. Thistle went straight up the park and Albinson pulled off a diving stop to prevent Danny Mullen making it 4-0 with the final kick.