The Scottish Communities League Cup holders have a free weekend in which to allow their first major trophy win since 1987 to sink in during the international break.
But when the SPL pre-split schedule resumes, they have three fixtures in store starting with Sunday week's visit of Celtic followed by away trips to Kilmarnock and Motherwell.
With bottom-placed Dundee enjoying a resurgence under boss John Brown, the battling Dens Park side have reduced the gap between themselves and the Paisley men to just 13 points.
And Thompson said: "The most important thing for us, now that we have won the League Cup, is that we don't get relegated.
"It has taken a few days to get our heads around Sunday and I think it is a big plus for us that we have the international break this weekend.
"But then we have to re-focus and switch our minds totally on to the Celtic game.
"Yes you want to enjoy the moment and savour it and none of us will ever forget what we achieved on Sunday, but we can't allow that to become tarnished with a relegation dog-fight."
Thommo produced a fine close-range finish to put Saints in front at Hampden and admits that the memory of that moment will stay with him forever.
He said: "As a Paisley boy, to score in a cup final for St Mirren and for us to go on and win the League Cup is just something that is from the pages of Roy of the Rovers.
"The great thing is that I have the League Cup winner's medal to prove it."
The former Scotland striker has no doubt that for the likes of teenage midfield talent John McGinn, Sunday's success can provide a real platform to great things.
Thommo said: "John is just 18 and already a League Cup winner.
"The experience he will have picked up on this run in the games, including the semi with Celtic and most importantly of all the final itself with Hearts, will provide such a valuable learning curve for him."