The Rovers’ right back opened the scoring in the first half but, after Jack Hamilton had equalised, he gave away a needless penalty from which Nicky Low scored the winner for Dick Campbell’s side who extended their lead at the top of the Championship.
Rovers by contrast have now gone five games without a win and only mustered three attempts on the part-timers’ goal.
Their bid to win the Championship is starting to falter.
Raith boss John McGlynn made one change to the team which took a point away at Inverness last weekend; striker Jamie Gullan making his first start since signing from Hibs with Ethon Varian dropping out.
The match was the last to be played in front of a reduced crowd of just 500 before Covid-19 restrictions are lifted on Monday.
The first half was forgettable in the main.
Arbroath pressed high and stopped Raith having too much time on the ball and when they did, they toiled to find space in behind the Lichties’ defence.
The visitors had a couple of attempts on the Rovers’ goal but Jamie MacDonald dealt with them easily.
But with less than five minutes to go in the first 45, Raith, who up until that point had offered nothing as an attacking force, took the lead.
Ben Williamson played the ball across the face of goal where Tumilty tapped it into the empty net with the Arbroath defence claiming for an offside in the build up.
It was Raith’s very first attempt, on or off target.
Neither side made a change at the break and the second half was just a minute old when the visitors equalised.
Scott Stewart found room on the right and crossed it where Jack Hamilton bundled the ball home.
The striker had another chance five minutes later when he was played through but took too long to make up his mind and allowed the Raith defence to block his shot.
On 62 minutes another attempt from Tumilty went narrowly wide before MacDonald had to look lively to block a shot from Stewart, who went close again shortly after.
Arbroath were looking the more likely of the two sides to score as the match entered the 15 minutes.
With 10 minutes to go a cross from James Craigen evaded the Raith defence and struck the inside of the goal.
From the same passage of play Tumilty then made a rash challenge on Colin Hamilton, leaving referee Steven McLean with no option but to point to the spot.
Low made no mistake.
A Colin Hamilton fierce drive was well saved by MacDonald before he saved again seconds later from a Stewart header.
Sub Aidan Connolly hit a shot over the bar as Raith pressed for an equaliser that never came against a side they now trail by six points..