Stoke manager Mark Hughes believes Manchester United lack confidence and that their players are racked with nerves.
Hughes won 11 trophies during his 13 years on the playing staff at United, but his Stoke side beat the 20-time English champions with ease at the Britannia Stadium on Boxing Day.
Hughes knew United's brittle confidence would shatter if his team applied enough pressure and he was proven right.
Bojan Krkic put Stoke ahead following a calamitous error by Memphis Depay and once Marko Arnautovic had found the net with a fierce 25-yard drive, there was no way back for United.
"United have gone three or four games without a win so it's a confidence thing," the Stoke boss said after his team's 2-0 win.
"It does you give you an opportunity to get a better performance and play well as a team.
"We talked about their levels of confidence because you have to drain as much of that as you can from the opposition because that allows you to grow as a team.
"I think that's exactly what we did in the first half. We didn't allow them to settle - any anxiety they had or apprehension about the game was borne out because in that opening period, we were really dominant."
Hughes feels Stoke have moved on from perception that they are just merely a difficult team to beat.
Shaqiri and Bojan caused United countless problems, particularly when they drifted wide.
And in Arnautovic they have a real gem of a player who is starting to listen to Hughes' advice.
"We tell him until we are blue in the face to shoot more, to be perfectly honest, because he has great power," Hughes said of the Austrian, who has scored six goals this season.
"Maybe that (goal) will encourage him."
Hughes also praised captain Ryan Shawcross, who kept Anthony Martial, Wayne Rooney and Marouane Fellaini at bay.
Once again the Stoke fans urged Roy Hodgson to end the centre-back's exile from the international arena and Hughes admits the former United defender can do little more to put himself back into the England manager's thoughts.
"He's been excellent for a long time," Hughes said.
"I thought he was outstanding. Our crowd are a bit biased on occasions but you heard them and what they were singing . It's credit to him - he just gets on with it.
"He's parked that side of his ambition. He just wants to do well for us. If it happens it happens.
"It's not a decision we can influence. All Ryan can do is just play well."
Shawcross diverted the praise on to Jack Butland, who saved brilliantly from Fellaini in the second half.
The Stoke skipper was reluctant to hail Butland too much, though, as he knows other teams will be watching the goalkeeper's progress.
"Jack is a top goalkeeper and we need to play down how well he is doing to be honest because someone will come in an snap him up," Shawcross said.