Angel di Maria admitted earlier this week that he had struggled to adapt to the style of Premier League football so far.
Manchester United forked out almost £60 million to sign the Argentine in the summer, but he has yet to justify the fee. Having started well, Di Maria seems to be only getting worse.
He said earlier this week: "I've had a couple of games where things haven't gone as well as they could have.
"I think it's part of that settling in process to the English game. I started off quite well but I think that made expectations then rise and everyone thought that I would just carry on in the same way.
His performance against Sunderland was possibly the worst yet. Not only was he ineffective against a less-than impressive Black Cats defence, but he looked disinterested with Manchester United's cause.
Never scared of a controversial substitution, Louis van Gaal withdrew his record signing in favour of Adnan Januzaj after just 45 minutes of action. Naturally, Twitter went crazy with Di Maria rocking up the trending list within minutes.
Here we take a look at some of the best tweets from disgruntled fans and respected pundits. Give them a minute to load - there are a lot of them.
Without Di Maria, Manchester United came back to life and scored two second-half goals from Wayne Rooney to seal a much-needed win. They temporarily move back up to third but Arsenal can regain their place with a win over Everton on Sunday.
The first came from the penalty spot after former Manchester United defender Wes Brown brought Radamel Falcao down in the box. The second came from the Red Devils captain from a close-range header having reacted to Januzaj's parried shot.
Manchester United fans! We want to hear YOUR views. Was Louis van Gaal right to substitute Angel di Maria after 45 minutes? Tell us in the comments box below!