Like Di Maria, Arsenal's Alexis Sanchez is South American, small in stature and with bags of pace and attacking skill.
Both of them arrived from a La Liga superpower in the summer for massive money, and with a big reputation too.
Unfortunately for United's £59.7m man, they do not have much in common when it comes to what they have done since.
For me, Sanchez has been one of the signings of the season at £35m from Barcelona, not far behind Chelsea duo Cesc Fabregas and Diego Costa – who look like they are going to win the league.
In contrast, Di Maria has been the biggest disappointment.
That is not just because his fee was a British record, but when you consider how good he is and what he had achieved before he signed.
'Di Maria was the third or fourth best in the world'
The reason there was such a buzz when United bought Di Maria from Real Madrid in August is that he was up there with the best players in the world.
He was man of the match in last season's Champions League final,which Real won, and he had a great World Cup.
Argentina definitely missed him in the final against Germany and, with him in the team, they arguably would have won it.
He showed that in September, a week after making his United debut, when he went to Dusseldorf and made three goals and scored another to help Argentina beat the world champions 4-2 in a friendly.
Di Maria played on the right flank that night and he was ridiculously good At that point, I would say he was probably up there as the third or fourth best player in the world. There was Cristiano Ronaldo and Lionel Messi… then Luis Suarez or him.
Now? It is like watching a completely different player – and a much less effective one.
Di Maria was back on the right in his last two games for United, and did next to nothing – he was replaced at half-time against Sunderland and taken off after less than an hour against Newcastle. That is just not good enough.
The very best players in the world are able to grab games by the scruff of the neck and lift their team when they are not playing well.
Sanchez has been a great example of that with the way he has regularly made things happen for Arsenal on the days when they have been average and have needed his help to help set the tempo in attack.
There is no way you could say that Di Maria has done the same for United while they have been short of their best form.
Yes he still works hard but, if anything, his performances have been getting worse, not better.
I highlighted on Match of the Day a couple of weeks ago how easily Di Maria was being knocked off the ball.
On top of that, his decision making has been poor and he looks short on confidence.
