CHRIS Innes scored the only goal as Aberdeen succombed to a tame defeat at New St Mirren Park.
The centre-back found the top corner with a half-volley from Andy Dorman's 74th-minute corner.
Innes also sealed a 1-0 victory over Kilmarnock on January 2 and the latest winner opened up an eight-point gap on bottom side Falkirk.
Gus MacPherson's side moved above Motherwell into seventh place, just one point behind their opponents.
"It's nice to have that cushion, you would rather be out it than in it," Innes said.
"But what the gaffer is focusing on is us looking up the way. I think that's a very positive thing. He sets our goals high, but we're not getting carried away."
The victory was St Mirren's first over Aberdeen since 2001 and their third on the trot following Saturday's Active Nation Scottish Cup win over Alloa.
"We're starting to do very well but the gaffer is keeping our feet firmly on the ground," the 33-year-old said.
"We're not getting any delusions of grandeur, we're taking it game by game.
"The pitch is very difficult, the ball is bobbling all over the place. But we dealt it as well as we could and it was just great to get the three points."
Charlie Mulgrew and substitute Chris Maguire hit the woodwork for Aberdeen but manager Mark McGhee was disappointed with his side's lack of cutting edge.
Aberdeen have only scored 13 goals in 18 SPL games and McGhee, who was without the suspended Lee Miller, is impatient for news on his pursuit of Plymouth striker Steven Maclean and Swansea's Stephen Dobbie.
"We're still waiting on the answers, the ball is in their court," McGhee said.
"It is frustrating because this time last week we looked as if we were going to have four games in quick succession.
"Falkirk next week, which is now off, and St Johnstone and Kilmarnock as well, and those were four games where I felt, if we got a strong squad out there, we would have a chance of taking a lot of points.
"We have tripped up at the first one and I think Miller would have made a difference, MacLean would have made a difference.
"It's disappointing we didn't have either of them and we've lost a game that we think we should really win."
Hearts 4/6, Draw 13/5, St Mirren 9/2
Source: Team Talk
Source: Team Talk