The Ecuador international moved to United from Wigan Athletic as a winger in 2009 but began his conversion into a full-back in the latter stages of Sir Alex Ferguson's career, and he was recently awarded a one-year extension on his Old Trafford contract.
The 31-year-old has started 18 of United's 21 league games so far this season in the right-back role and, for Mourinho, there is no better player in the world in the position, per MUTV (h/t United's official website):
"I don’t think [the contract extension] is a reward, I don't see it in this perspective. I just think he is the best right-back you can have. There is no better right-back in football. It is just for us to keep the best. I don't think it is a reward. It is a privilege for us to have such a good player and such a good man."
Memphis Depay's departure from United to French club Lyon was confirmed on Friday just a season-and-a-half after former manager Louis van Gaal signed him, per BBC Sport.
Mourinho said the Dutchman struggled to make the first team due to United's wealth of wingers and confirmed that the Manchester club have a buyback option on the 22-year-old, per Samuel Luckhurst and Alex Porter in the Manchester Evening News:
Because potentially he's a very good player. When Mr Van Gaal decided to buy him he did well, he knew him very well, he was very young at the World Cup, he had flashes of top quality, he was playing well in Holland, we know the Dutch league is not the same but he was showing very good things.
He didn't succeed in his 18 months but he's very young so I think it's important for the club to complete control in this talent and we wish he plays very well at Lyon and why not to come back because everyone here likes him.
United's nine-match winning run was brought to an end when they drew with Liverpool on Sunday, but Mourinho's side remain unbeaten since early November.
They will be looking to make amends at the bet365 Stadium on Saturday after claiming only a draw in the reverse fixture against Stoke back in October despite carving out numerous opportunities.
Mourinho confirmed that only a victory will be acceptable against the Potters, per United's Twitter account:
Manchester United @ManUtd
Jose Mourinho says #MUFC's unbeaten run is not his focus v Stoke: "We want to win matches, we try to win matches, we risk to win matches."2017-1-20 12:39:25
He also had good news on the injury front, per ESPN FC's Ben Dinnery:
Ben Dinnery @BenDinnery
Mourinho on injuries: "We have little problems, which is normal, but not [they are not] big issues. We have a very good situation." #MUFC2017-1-20 12:31:50
With fifth-placed Manchester City just two points ahead of United and facing in-form Tottenham Hotspur at the weekend, the Red Devils will likely be hoping they can leapfrog their local rivals with a victory against Stoke.
Given the form of those above them in the table, any more dropped points could be disastrous for United, and they have enough quality to beat Stoke even away from home.