Jose Mourinho tried to sign Antonio Valencia when he was at Real Madrid and always saw him as a potential star at right-back.
The Manchester United boss was in charge at Santiago Bernabeu between 2010 and 2013, when Valencia was a winger in the early stages of his Old Trafford career.
The 31-year-old has since been reinvented as a full-back and has started 10 of United's 12 Premier League games - only missing time for a broken arm - under Mourinho, who has long been an admirer.
"I tried to sign Antonio a number of years ago, when I was at Madrid," Mourinho said to MUTV.
"Even though he was not playing right-back at the time, I thought he could be phenomenal in that position. As it was, United told me 'no chance!'
"I am not surprised by his form this season. He has been clean of injuries, save for an operation on his arm which did not keep him out for long, and I have also been able to keep him fresh by resting him in certain Europa League games.
"I think he is the right-back to give us the maximum we can in terms of our attacking football."