Simon Murray scored in each half to leaven Dundee's Scottish Premiership's relegation fears and simultaneously dent St Mirren's top six hopes.
It took just two minutes for Murray to lift spirits around Dens with a smart strike and another attempt after the break, capitalising on a Zach Hemming mistake, took the 33-year-old level with Daizen Maeda as the division's top scorer with 15.
It also moves his side eight clear of bottom side St Johnstone, who host leaders Celtic on Sunday, and close to Motherwell and Ross County as well as St Mirren, whose top-six hopes will be over if Hearts beat Dundee United on Sunday.
The visitors had threatened first, Mark O'Hara having an attempt from 16 yards blocked by Trevor Carson's knees, before Murray's opener.
Oluwaseun Adewumi kept Jordan McGhee's cross alive and Murray pounced to hammer home his 20th goal of the campaign in all competitions.
St Mirren's Jonah Ayunga was guilty of a glaring miss with a header but his side - who won so handsomely against Kilmarnock last weekend - started the second period strongly.
Caolin Boyd-Munce tested Carson, who was again called into action when O'Hara fired in an awkward low free-kick from the left edge of the box.
However, Tony Docherty's hosts doubled their advantage after a shocking mistake by Hemming.
The keeper's attempted a kick out hit Murray and the striker reacted sharply to roll the ball into the net from 35 yards as the hapless Hemming scrambled back in vain.
St Mirren kept pushing and Richard Taylor had a header off the crossbar on what turned out to be a frustrating day for the Paisley side.