The Paisley men have conceded 12 goals in their last three games against the Hoops without reply, but while the Buddies could have been forgiven for travelling with only forlorn hope to the East End of Glasgow, Thommo reckons his side can shock the Bhoys.
The former Rangers spearhead believes that a four-game unbeaten run which has seen Saints become a lot more solid at the back is decent form to take to the home of the Celts, but ultimately admits that his side's hopes will rest on star alignment.
Thompson said: "We know how tough it will be to get anything from Celtic Park and equally we know that our record there has been anything but impressive.
"However, there would be no point travelling if we did not go with belief we can end our bad run against them and take something from the match.
"Realistically a lot of things will have to go our way and it could be a case of star alignment in that regard. Every one of us needs to be at our best while we need four or five of the Celtic players to be off their games.
"But we know that Celtic have better players than us and we know that they have so much quality in depth that it is going to be a massive task.
"That said, as professionals you want to play against the best and right now when it comes to Scottish football that means playing Celtic.
"We have worked very hard on our shape and our organisation ahead of this one and that is going to be vital. It is going to take a huge team effort but one we are capable of."
The Paisley poacher will be locking horns with an old foe from his time down south with Burnley when he lines up against Kelvin Wilson.
Thommo admits that the ex-Nottingham Forest stopper's new partnership with Efe Ambrose is an intimidating one to play against.
The Saints talisman said: "I played against big Kelvin a fair few times down south and he is a tough uncompromising sort who never gives you an inch. I think it has taken him time to adjust his game to the move to Celtic and to settle in at such a huge club but, now that he has, he is starting to show his true qualities.
"I played against both Kelvin and Efe Ambrose the last time we played Celtic and came off second best by quite a way. Ambrose is very similar to Kelvin in his physical attributes.
"But I am looking forward to the challenge they will pose me and fingers crossed I can give as good as I get."
After noting the quality of the Celtic defence, Thompson also commented on the Hoops mentality, and insisted a good start is vital to the Paisley side's hopes of upsetting the odds.
He added: "Looking back at the last game we had with Celtic, we were three goals down in 30 minutes and the game was over. On Saturday it will be vital that we make sure to give Celtic absolutely nothing.
"When you play at either Old Firm ground the first thing you have to do is silence the crowd and if we can do that we will have given ourselves a chance."