Earlier in the season the 23-year-old right-back, like most players and fans in Scotland, witnessed Saints struggling to get their campaign up and running with manager Danny Lennon coming under increasing pressure following eight games without a win.
However, after two successive victories, the Buddies seem to have turned the corner but Watson, who came through the youth ranks at Tannadice, is looking to bring that to a halt.
He told Press Association Sport: "They didn't have a great start at all.
"You were looking at the results and thinking 'St Mirren have been beaten again'.
"Obviously you are going to be under pressure but the St Mirren chairman stood by him (Lennon) and the results are starting to pick up now.
"In the past couple of games they have got two wins and they are absolutely buzzing now.
"They will be looking to make it three on Saturday but we will be looking to stop that, definitely.
"But they are playing well so it will be a tough game."
Jackie McNamara is confident Gary Mackay-Steven can shrug off a knock, while defender John Souttar, who was rested for the trip to Aberdeen last week, is back in contention.
New St Mirren goalkeeper Marian Kello has vowed to win a long-term deal by helping the Buddies move up the Scottish Premiership table - but admitted he could not bring himself to contemplate relegating former club Hearts.
The 31-year-old Slovakia international has penned a 10-week contract with Lennon's side just 18 months after walking away from Tynecastle.
He was frozen out by former owner Vladimir Romanov after turning down a move to Austria Vienna, but insisted he still had a soft spot for the Jambos.
However, when it was pointed out to him that by helping struggling St Mirren survive in the top flight this year he could help relegate Gary Locke's men following their 15-point deduction for going into administration, Kello refused to even consider that dreaded fate.
He said: "I don't want to think like that. I will try my best for the club I am at now. That is all I can do.
"It's not nice or easy to see Hearts where they are. This club and its supporters deserve much more. Unfortunately they are there and they need to go with the future and hope it gets better.
"I have sympathy with what the players are going through at the club. There are so many talented players there and it's such a shame they are in this situation. There is a lot of pressure on them and it's not fair because they deserve to be in a better situation."
Kello negotiated an early release from his Hearts contract in April last year and went on to have spells with Romanian side Astra Giurgiu as well as Wolves in England's Championship.
However, he was not offered a new deal with the Molineux side and then failed to win a move to Doncaster following a trial.
But Kello - who also played with Romanov's Lithuanian side FBK Kuanas - arrived in Scotland on Wednesday to answer an emergency call from Lennon after he lost keepers Chris Dillo and Kieran Hughes, leaving him with just on-loan Swansea stopper David Cornell to fill in between the sticks.
He could now feature against United at Tannadice on Saturday and is hoping to earn himself a longer stay in Paisley.
Defender Marc McAusland is also available after an ankle knock but Gary Teale's groin injury costs him his place, while David Barron is still out with his own ankle problem until Christmas.