And Ferdinand, who enjoyed a trophy-laden career at United between the years of 2002 and 2014, believes that the Chile worldwide has more chances of winning silverware with Pep Guardiola's side.
The 29-year-old Chilean worldwide is heavily linked with a move away from the Emirates this month, with his present deal expiring in the summer.
Guardiola's bid to buy Sanchez collapsed at the end of the summer transfer window and City were favourites to land him this time around but the club are apparently unwilling to meet Arsenal's reported £35 million ($48 million, 39 million euros) asking price.
"At this stage, I don't think it's about the market", said Mourinho, whose United hosts Stoke City on Monday.
Manager Antonio Conte has confirmed that the Premier League champions will not be taking part in the transfer battle to sign Arsenal's Alexis Sanchez.More news: Klopp: I coped with losing Sahin, and will with Coutinho
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United is said to have presented Arsenal with a bigger offer than City, and although Mourinho claims it was not in the club's plans to sign players in January, he acknowledged that fantastic opportunities are worth pursuing whenever they present themselves.
In relation to Sanchez all I can say, which everyone else says, is that he is a phenomenal player. The 29-year-old is understood to prefer a move to City, and to work again with his old Barcelona coach Guardiola.
"He'll have the choice of a lot of clubs and, if United could get him, it would be a massive signing".
Speaking of Sanchez's possible arrival, reports have suggested that Henrikh Mkhitaryan could be headed the other way in a player plus cash deal.
" It looks like Sanchez will not extend his contract.These guys want to win, and they want to make money as well".
Goal revealed on Friday that Manchester City remain hopeful of completing a January swoop for Sanchez, despite United having joined the chase. However, he and his agent are understandably considering United's offer, and any deal could depend on Arsenal securing a replacement, with Bordeaux's Brazilian forward Malcom said to be their main target. But sometimes it can happen: on the table there's a fantastic opportunity and you fight for that opportunity.