The thrashing at the hands of Neil Lennon's slick Celts was the Paisley men's first defeat in four games and also their heaviest reverse of an otherwise impressive season.
But the former Celt insists there will be no protracted post-mortem as he has already set his sights on returning to winning ways when Inverness visit Greenhill Road on Saturday.
McGowan said: "The important thing for us to remember is that our season will not be defined on how we do at either of the Old Firm grounds.
"We knew it would be tough at Celtic Park with the type of run they are on and the momentum they have built up and losing the early goals did not help.
"But Celtic have the type of firepower that can do what they did to us against any side at Parkhead. So we have taken a sore one and now we will move on from it.
"What has to take all our focus is the home game with Inverness on Saturday. That is where our season will be made into a success or otherwise.
"We have the character in our ranks to respond to this defeat and it is definitely a plus that we have a home game to do so, against Caley Thistle, on Saturday."
McGowan's sparkling performance at Parkhead was one of the few pluses for the Paisley men.
Always available and able to elude the attentions of his markers with trademark trickery before finding a colleague, McGowan once again proved that he has the quality to flourish at a higher level.
With fellow youngster Kenny McLean also impressing early before the roof fell in on Saints, manager Danny Lennon at least has the comfort of knowing he has players in his ranks who have the ability to prosper against the best the domestic game can offer in Scotland and the nerve to go with it.
Yet, with Saints gift-wrapping two early goals to Neil Lennon's side – just as they had done in the previous meeting between the two sides at Greenhill Road back in August – McGowan admitted he had been hit by an overwhelming sense of green and white tinged déjà vu.
He added: "The one thing you can't afford to do when you go to the Old Firm is give them cheap goals early doors and we committed that sin.
"It was almost a carbon copy of what happened in our first game with Celtic at St Mirren Park and we just made life very difficult for ourselves.
"What we must make sure we do is learn our lesson this time.
"But we are a young side who are developing and progressing all the time and we won't let this result derail us."