Despite flashes of brilliance at time this season, the Argentina midfielder has failed to deliver consistency for Manchester United who he joined from Real Madrid last summer.
The 27-year-old has also played for Portuguese giants Benfica and he told the United website: “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 then made expectations rise and everyone thought I would just carry on in the same way.
???But football is like that, sometimes you have these ups and downs. It took me a while to settle fully in each of the countries where I???ve played before.
???I just have to keep working hard and focusing on what I want, which is to do as well as I possibly can.”