The Paisley men are desperate to put a three-game winless SPL streak behind them and, with the Tynecastle outfit just one point above them, Samson says the motivation to claim a three-point haul could not be higher.
But the Buddies No.1 has warned his team-mates they will need to tighten up defensively if they want to get back to winning ways – and he has made a clean sheet the priority for tonight's Greenhill Road clash.
He said: "I feel that in both of our last two outings we were worth a share of the spoils at least, but that we shot ourselves in the foot with some disappointing defending.
"Against Hibs, the game turned on a penalty while, in the St Johnstone match, it was all down to one awkward ball into our box not being dealt with.
"Although we lost these two games, there was only one goal in both and, while that underlines the fact we have been very competitive, we need to give the opposition no assistance. In our first match with Hearts we defended solidly to record a 2-0 victory. It was all about giving ourselves a platform, and we have to do that again tonight.
"They are sitting just above us and we have the perfect opportunity to make the most of home advantage and get above them.
"If we are to have any hope of clawing our way back into the fight for a top-six place, this is a game we must win."
The visit of John McGlynn's side is also a dress-rehearsal for next month's Scottish Communities League Cup Final at Hampden, but Samson says that will have no bearing on this evening's encounter.
He said: "We have the final coming up against Hearts at Hampden, and before that a huge Scottish Cup quarter-final with Celtic on Saturday, but the last thing we can afford to do is let our focus slip towards these games."
Samson reckons Saints will need to be aware of the threat posed by Liverpool loan signing Michael Ngoo. The keeper said: "He has scored three goals in three games and you are not at a club like Liverpool if you don't have some real quality in your locker.
"They are giving their young lads a chance, and they are hungry to take the opportunity they are being given and make the most of it and that is something we must take into account.
"But this is a real opportunity for us to get going again, and it is one we can't afford to pass up."