Bojan Miovski tucked away a second-half penalty to settle the match
Aberdeen moved 10 points clear of the drop zone, erasing any worries of a play-off, with a narrow victory over St Johnstone.
The Dons struggled in front of goal despite numerous chances but Bojan Miovski was there to convert from the spot after Andrew Considine's foul on Nicky Devlin prompted referee Chris Graham to award a penalty.
The Saints drop into the relegation play-off spot after Ross County's victory over Hibs.
The Perth side are two points behind the Dingwall side with three matches remaining.
An uneventful first half at Pittodrie finished goalless but with Aberdeen on the front foot.
The home side’s best chances of the game fell to Stefan Gartenmann who headed over from a whipped in corner before bolting back up the other end to clear Benjamin Kimpioka’s effort off the line.
Just before half-time, the defender was one on one with Dimitar Mitov in the St Johnstone goal after Junior Hoilett’s free-kick smashed the crossbar and fell back into the box but once again he could not get it on target.
Nicky Clark saved St Johnstone from conceding a certain goal in the early stages of the second half. His clearance off the line, with his hip, drew penalty claims but they were waved away.
Minutes later, the home side were once again claiming for a handball after the ball struck Liam Gordon on the arm but it seemed as though the Saints defender headed the ball down onto his arm, so no penalty.
Miovski settled the match from the spot on 68 minutes. Devlin went down under the challenge of Considine and although there was not a huge amount in it, VAR did not see any reason to overturn the referee’s onfield decision.
Adama Sidibeh had the best chance for the Saints when he fired over the crossbar from close range.
Player of the match - Junior Hoilett (Aberdeen)
The Dons attacker looked a threat all afternoon and was unlucky not to get on the scoresheet himself when his wonderful free-kick struck the crossbar.
Dons creep to safety - analysis
Aberdeen had been on the up since the split but it was a contentious penalty that secured a first win of the season against St Johnstone.
For a striker that has been so reliable this season, Miovski really struggled in front of goal and missed several big chances.
Despite a tough afternoon, he held his nerve to convert from 12 yards.
Junior Hoilett looked a threat all game and even hit the crossbar with a wonderful free-kick and the rebound should have been converted by Stefan Gartenmann, who was one-on-one with Mitov.
St Johnstone fought hard but that is now five defeats in their last six league outings.
They got forward, created chances, but lacked the clinical edge needed to get back in the game after going behind.
What the managers said
Aberdeen coach Scott Anderson: "We're pleased to win the game and another clean sheet. I don't think there was a lot in the game in the first half but in the second we had much more control.
"Can we improve? Absolutely and we'll look to do that over the course of the last three games."
St Johnstone manager Craig Levein: "It is important we put that to one side and forget about it.
"We've played the two best teams in the bottom six and we've got Livingston, Ross County and Motherwell to play. Tough challenges, but I think we can get nine points."
What's next?
Aberdeen travel to Easter Road to take on Hibs on Sunday 15 May, that one kicks off at 15:00 BST while St Johnstone are in West Lothian on Saturday to face relegated Livingston, that one also kicks off at 15:00 BST.
