As a result, much of the play was concentrated into a midfield battle, with little guile from either side.
Ryan Hedges had the home side in front just before the half-hour with a low drive, but Tommy Wright's men levelled 15 minutes later thanks to a Michael O'Halloran shot Joe Lewis will feel he should have stopped.
Aberdeen first threatened in the 17th minute. Left-back Greg Leigh crossed from the left, right footed, finding Sam Cosgrove. The Englishman's header took a deflection off Scott Tanser and wrong-footed goalkeeper Zander Clark but the ball came back off the post.
The Dons took the lead 10 minutes later, and again Leigh was involved. He won the ball back in an advanced position and knocked it though to Lewis Ferguson, who in turn found Hedges.
The Welshman was all alone and drilled a low strike past Clark from the centre of the box.
However the visitors were level two minutes from the interval. O'Halloran's shot looked routine for Lewis but the ball seemed to bobble in front of him and it found the bottom-right corner of the target.
Saints were buoyed by their goal and were the better side in the early exchanges of the second period, with Jason Holt taking hold of the midfield. Twice he teed up Murray Davidson - the first, from a right-wing corner, saw the midfielder head wide, the latter saw Lewis push an angled drive around the post.
There was controversy after 63 minutes as Matty Kennedy went down under pressure from Andrew Considine.
Referee Steven McLean gave the award from behind the incident, but Assistant Referee Graeme Stewart had an unobstructed view and was unmoved. After consultation between the two, the decision was reversed.
That seemed to take away any momentum the visitors were building, but the home side did not exactly push on.
They did, though, have a final chance in added time as Lewis Ferguson lined up a 25-yard free-kick that took a deflection before being palmed away by Clark.