BUSTLING Billy Mehmet grabbed his second goal of the season as the Buddies put more daylight between themselves and their relegation rivals.
Mehmet's first-half strike fired Gus MacPherson's men six points clear of Gretna who must now fear becoming isolated at the bottom.
The SPL new boys fought to the death but St Mirren always had the edge and could have won by more.
To compound Gretna's misery Craig Barr was sent off three minutes from time after picking up a second yellow for a rash challenge on defender Will Haining. St Mirren goal hero Mehmet said: "Even though it's early you want to create a gap between youselves and the team at the bottom.
"Hopefully I can get a few more goals. I have a target in mind for the season but I'm keeping it to myself."
MacPherson handed assistant manager Andy Millen his first start of the season in one of four changes.
His new-look side settled quickly and Gary Mason was out of luck with an early shot after an excellent break down the right by Hugh Murray.
Home keeper Chris Smith then sparked an attack with a huge throw out to Marc Corcoran. The winger bombed down the right and sent over an inviting cross that was just out of Mehmet's reach.
St Mirren kept forcing the play and the impressive Murray headed a Chris Birchall free-kick wide.
Gretna's first real effort was a 35-yard free-kick from Fabian Yantorno that curled just over the bar.
Skipper Paul Murray was next to fire the ball over after a misplaced pass by Mason set up a chance.
Buddies stopper Haining showed he could be a powerful presence at both ends when he went upfield and headed a Millen cross just past the post.
He was then under threat at the other end as Gretna came close after 33 minutes.
Murray set up Yantorno and the Uruguayan smashed in a powerful drive that Smith touched over the bar.
It proved to be a vital save as St Mirren grabbed the lead just a minute later.
Millen played the ball wide to Franco Miranda and Mehmet got on the end of his curling cross to prod the ball past keeper Greg Fleming.
Suddenly the Paisley fans found their voice and the players responded by keeping their opponents on the back foot until half-time. Gretna boss Davie Irons clearly hadn't been happy with his side's attacking play and made changes at the break.
He sent out David Graham and Mickael Buscher in place of David Cowan and James Grady as the Raydale men tried to find a leveller.
But St Mirren started where they left off and should have scored six minutes into the second period.
Murray found Alex Burke with a crossfield pass and he took a touch before firing a left-foot shot inches wide.
Just before the hour mark Gretna made another switch with Colin McMenamin on in place of Yantorno. MacPherson responded by swapping Burke for Stewart Kean as he tried to find a killer second goal.
The Buddies boss almost got it in 65 minutes as Gretna had a double escape.
Fleming did well to save a point-blank Kean header and as the Love Street men kept the pressure on, David van Zanten thumped a shot off the bar. However, Gretna never stopped trying in their search for a leveller and had a good spell of pressure late on. But they almost shipped another goal when substitute Stephen O'Donnell, who had replaced Birchall, had the ball in the net after Fleming parried a Kean shot.
However, he was offside.
REF WATCH
MIKE TUMILTY tried to keep the game flowing and played one good advantage in the first half for Gretna. But he needed one of his assistants to let him know about a blatant handball he somehow missed. That aside it was a decent performance from the whistler. Rating: 6/10.
SPL 
