Ayr will go into the second leg of the Premiership play-off quarter-final with a small lead following a 1-0 win against Partick Thistle at Firhill.
Jamie Murphy scored the only goal of the match 10 minutes after the break, giving Scott Brown’s team the advantage for the upcoming return game on Friday.
The match was cautious and had many interruptions. Brian Graham missed three chances for the hosts, while Ayr's goalkeeper Josh Clarke didn't face many threats.
Partick Thistle played without Sean Kelly, who got injured and will be out for the rest of the season after their 1-0 victory over Livingston.
Ayr made six changes, including a forced substitution due to an injury to George Stanger, which led to a reshuffling of the defense.
Early in the game, Nick McAllister had to be replaced in the 10th minute after a head injury following a collision with Robbie Crawford.
The first notable opportunity came in the 15th minute when Marco Rus's shot was saved comfortably by home keeper David Mitchell.
Thistle's captain Graham forced a great save from Clarke with a header from Aidan Fitzpatrick's precise cross in the 30th minute.
There were appeals for a penalty shortly after as Crawford went down in the box, but the referee was unmoved.
Graham missed another good chance just before halftime, heading Crawford's free-kick narrowly wide.
On the other side, George Oakley missed the target hitting the side-netting after a pass from Rus.
Ayr broke the deadlock in the 55th minute when Murphy scored with a header from Connor McLennan's cross.
The home crowd tried to motivate their team, but Ayr remained the more dangerous side.
McLennan's shot narrowly missed the target with Thistle's keeper struggling to reach it.
O'Reilly received a yellow card for a foul on Dylan Watret, making him the fifth Thistle player to be booked.
With five minutes to go, Lawless couldn't find a teammate after a positive run forward, causing frustration for the home fans.
Six minutes of added time gave hope for Thistle to equalize late in the game.
The closest opportunity came in the 91st minute when Graham's header from O’Reilly’s delivery went just wide, marking the last chance in a disappointing night for the home team.