A clear case of mistaken identity surely - and not just because referee Roger East sent off Sunderland's Wes Brown instead of captain John O'Shea.
No, the identity crisis continued to surround United. With Angel Di Maria - pounds 59.7?million Angel Di Maria - 'hooked' at half-time; with the home supporters chanting "attack, attack, attack" midway through a laboured first half as another back-pass was attempted. And with Louis van Gaal looking more than a little uncomfortable in the dugout. This was a pale shadow of where this club want to be and how they want to play.
There was more. Here was Wayne Rooney scoring the two goals as he played as a striker - the role he wants to fill and which Van Gaal has resisted using him in for much of this campaign as he strives to find his best permutations.
With Van Gaal having lamented that he does not have a 20-goala-season striker Rooney moved into double figures and became the first player to score 10 or more goals in 11 consecutive seasons since the Premier League was launched in 1992.
But the biggest identity crisis, once the debate is had over the rights and wrongs of Brown's dismissal, concerned Di Maria, who appeared a nervy, confidence-sapped, fragile, pale shadow of the player who was man of the match in last season's Champions League final for Real Madrid and who set the pulse racing when he joined United last summer.
Di Maria was knocked off the ball, his passing was awry, his shooting wayward, his decision-making poor. He struggled to make any impression beyond a man who is simply struggling and was inevitably substituted at half-time. What ignominy for such a world-class player. But it made sense.
"These are your words," Van Gaal said when asked whether the Argentine was, indeed, struggling. "I want to win and as a manager I have to observe and analyse and then make the steps that are necessary to win. I saw that I had to change Angel for [Adnan[ Januzaj and we were in the second half better so I cannot say it was a wrong decision.
"The difficulty, and it is not only with Angel, is that the players have to adapt to the Premier League. I have explained already that the rhythm of the game is so high, much higher than other countries and he has to adapt to the culture. We have to give him time and also to lift his confidence."
It is not just Di Maria. There is Radamel Falcao also, even if he earned the penalty. "Because of the same reason," Van Gaal said of his decision to substitute the Colombian. "I was very pleased with his action for the penalty but I have to win and I thought, at that moment, we need to keep the ball more and with [Marouane] Fellaini it is more easy to keep the ball up front."
If that appeared disjointed then it was. And so were United. The first half was a struggle - for players and fans - with the home side going close only when Ashley Young's fierce cross-shot was deflected inside the six-yard box by O'Shea onto the Sunderland crossbar and Sebastian Larsson cleared a goal-bound effort from Marcos Rojo.
For Sunderland, there were half-chances for Jermain Defoe and more than that for Connor Wickham, but he shot weakly at David De Gea who nevertheless injured himself in saving.
Van Gaal put the performance down to "nerves" having lost against Swansea City (he also professed not to hear the chants imploring his team to attack) but the contest had to be fast-forwarded to after an hour before any real quality began to emerge. It came from Falcao, who had found the going tough as he was physically dominated by Brown but he deftly took down a cross fired at him by Ander Herrera and then flicked the ball beyond O'Shea.
The defender fouled him, then grabbed him and Brown ran across. Falcao hit the turf, falling as he attempted to shoot and the penalty was given. That all seemed clear enough but then East produced the red card - and showed it to Brown. He was disbelieving, as was O'Shea, who tried to reason with East. The referee was clearly listening into his earpiece as he assessed the developing situation.
The Sunderland captain even attempted to hand his armband to Lee Cattermole and walk off - but East insisted it was Brown who had to go. Eventually he did.
Poyet claimed that the referee told his players that both O'Shea and Brown had fouled Falcao but that did not appear to be the case - as replays also confirmed. Even if it was, then the first offence was by O'Shea. It was chaotic, confusing and the fear is the officials will close ranks.
Whatever happened - and happens now - it was a penalty. Rooney stepped up and drove the ball low into the net. Against the 10 men the result was never subsequently in doubt and eventually, even if they continued to labour, United did add a second goal to provide some further relief.
The goal came as Januzaj's shot was pushed out by goalkeeper Costel Pantilimon and there was Rooney to reach the rebound and guide his header into the open net. He, too, was then substituted. But at least that decision made some sense - even if he was denied the opportunity to collect a hat-trick.