Results elsewhere meant that Morton secured a play-off place but, in extending their winless sequence to seven matches, they did little to suggest that they can negotiate a passage into the top tier.
Bottom side Ayr United earn a valuable Scottish Championship point at Morton, moving within two points of St Mirren.
A Peru-based Ayr United fan's design for a new club badge will be adopted next season after winning an online poll.
Dundee United missed the chance to leapfrog Falkirk into second place as their poor away form continued. Ray McKinnon’s men wasted good chances and were hanging on the ropes as Ayr threw everything into attack but were foiled by Cammy Bell.
Ayr United and Dundee United draw a blank in Saturday evening's Scottish Championship match.
Stephen Dobbie nets twice for the visitors as Ayr United drop to the bottom of the Championship.
A double from Stephen Dobbie swept Queens to a convincing win and sent Ayr to the bottom of the league, writes Robert McBride at Somerset Park .
Cancel the wreath and put those Greenock street parties on hold as reports of St Mirren’s imminent demise have been greatly exaggerated, and are more than a touch premature.