Sunday's 3-2 victory over Celtic at Hampden has set up a final with Hearts that will be the biggest day in the 24-year-old's career by a distance.
But with Inverness the visitors in tonight's SPL clash at Greenhill Road, McAusland is determined to slap the blinkers on and focus solely on reaping a vital three-point haul.
The Saints centre-back said: "Obviously we were all on a high after the Celtic win. It was just a massive result and a great performance against the best team in Scotland but it has gone now and it is vital we don't allow it to distract us from the Inverness game tonight.
"The SPL is our bread and butter and we know that we are not where we want to be in the table and also that last time out we let ourselves down against Ross County.
"So what we can't afford to do is to turn in a performance like we did against Celtic and then slip off it when it comes to Inverness.
"We have a great benchmark for the season going forward and it is vital that we maintain that level."
With both previous games between the two sides ending in 2-2, there has been nothing to choose between the Paisley men and their Highland foes this term.
But McAusland is in no doubt about how important it is to start making the most of home comforts after the County catastrophe last time out.
He said: "Defensively we sold some cheap goals against County and there can be no repeat of that.
"I think we have had 12 home fixtures this season and we have won just four of them and lost five, drawn three.
"So it is vital that over the second half of the season we improve that.
"If you are winning at home it takes a lot of heat off on the road.
"The other aspect of that is that we had a great support at Hampden on Sunday and they will no doubt be out in their numbers again tonight and we need to give them pay back.
"The St Mirren support may not be the biggest in the SPL but they are always there and right behind you. They made a real difference on Sunday."
Saints woes against the Hoops have been well documented since gaffer Danny Lennon came to the Paisley club with eight successive losses shipped prior to Sunday and 22 goals conceded and none scored.
McAusland was keen to pin point the difference at Hampden.
HE said: "For me I think the big plus was that we stuck to the game plan and did not concede either the first goal or an early one for that matter.
"We knew that on the day we needed everyone of our boys to play to the top of their game and that hopefully one or two of Celtic's players were not at their best and I think that is how it panned out.
"But if we want to underline the fact we are a decent team then we have got to be more consistent in the SPL.
"That has to begin tonight when we entertain Caley Thistle.
"They are going great guns this season and are sitting second in the table which is fantastic for them so we are under no illusions as to how difficult a game we face."