Saints were sharp off the block with a second minute Darren Sheridan corner threading through to John Henry, whose tightly-angled effort was blocked at the near post by Queens keeper Colin Scott.
In a half of few scoring opportunities, Saints pulled ahead in the 20th minute after a brave diving header by skipper Kevin James bounced off defender Derek Lyle to Jason Scotland. The Trinidad and Tobago striker, who faces the mouth-watering prospect of a summer World Cup clash with England, threaded the ball into the net for one of the easiest goals he is ever likely to score.
James was off the park for eight minutes getting treatment for a head cut and was later unable to restart the second half with suspected concussion and was replaced by Steven Anderson.
Neither side showed much composure in a second period where passes went astray all over the pitch. With arch-championship rivals St Mirren collapsing at Dundee, it was a relief for the home fans when Stevie Milne doubled the Saints score, drilling the ball under substitute keeper Richie Bernard in the 64th minute.
A late strike by Gary Wood flattered the visitors somewhat, although it was a goal of genuine quality.
Manager Owen Coyle is clearly looking forward to the prospect of meeting St Mirren next week, where a victory would put his side within a point of the league leaders.