It was a sloppy display from John McGlynn’s side punctuated by unforced errors and poor passing throughout as they lost a second league game in a row for the first time this season.
Ayr were well worthy of the three points and could even afford the luxury of missing a second half penalty.
Raith made two changes to the side who were beaten away to Partick Thistle.
Tom Lang slotted into the centre of defence for the suspended Christophe Berra, whilst Ethon Varian took his place up front with Aaron Arnott dropping to the bench.
Ayr took to the pitch at the empty Somerset Park under the watchful eye of caretaker boss, David White, who was handed the reins after Jim Duffy left at the beginning of the week.
The first 15 minutes were fairly equal, the closest Raith came to a goal was a shot from Varian which was well blocked, with a Ross Matthews header easily saved on the 20 minute mark.
But it was the home side who would take the lead on 21 minutes via a late Christmas present from the Rovers defence.
The goal gave the home side a boost and they took control of the game, putting the Rovers rearguard under pressure and could have had a second with half an hour gone when James Maxwell had a chance from a corner but put his shot wide.
Three minutes later Dario Zanatta came close to connecting with a low cross from Tumilty as Raith looked to get back into the match.
Rovers had a let off on 36 minutes when Tumilty was guilty of yet another loose pass which Paddy Reading picked up and his curling effort bounced off the Raith crossbar with MacDonald beaten.
Five minutes later and it should have been 2-0.
A great move from the home side ended with a cross from Mark McKenzie headed wide by an unmarked Steven Bradley who really should have scored.
Half time arrived with the Honest Men deservedly ahead after a flat first 45 from Raith.
Though no doubt having received a John McGlynn rocket during the break, Raith still toiled in at the start of the second half, with Ayr looking dangerous on the attack and comfortable in defence.
A second goal almost arrived on 58 minutes when a corner landed with Bradley who was unmarked at the back post but he fired his effort into the side netting.
Three minutes later Raith passed up a golden opportunity to equalise. Aidan Connolly’s free kick was put wide by Varian who should at least have hit the target.
Another free kick led to a half chance for captain Kyle Benedictus who headed over whilst under pressure.
At the other end Ayr passed up another chance for a second. Andy Murdoch beat the offside trap and his cross was put over the bar by Bradley.
A minute later a shot from Adeloye hit MacDonald and rebounded onto the post and was cleared.
On 71 minutes a low shot from Dylan Tait went agonisingly wide before the hosts finally got the second goal.
James Maxwell played in Mark McKenzie who had plenty of time to compose himself and blast the ball into the net.
On 78 minutes it should have been 3-0 when Ayr won a penalty but Adeloye’s attempt was well saved by MacDonald.
The same player went close four minutes later as he rolled an effort wide of the post as Raith committed men forward to try and get back into the match.
But it was the home side who should have added a thrid. A cross from sub Jonathan Afolabe was missed on the goal line by Maxwell.
The match ended with the points staying in Ayrshire on an afternoon to forget for the Stark’s Park side who didn’t manage a single effort on target.