The Red Devils paid Juventus a record-breaking £89 million fee in the summer of 2016 to bring a former product of their academy system back to Old Trafford.
Pogba has struggled to justify that price tag in his debut campaign, with fellow Premier League midfielders eclipsing his efforts.
Spurs star Alli falls into that category, with another goal in a 4-0 victory over Watford taking the England international onto 20 for the season for club and country and further increasing his value amid talk of interest from Real Madrid.
Former Tottenham midfielder Redknapp told the Daily Mail: “If you asked at the start of the season whether Paul Pogba or Dele Alli would be worth more come May, the Frenchman would have won every time.
“After a sensational campaign, Alli has eclipsed Pogba.
“If the United midfielder cost a world-record £89million, then what does that make Alli worth? He is becoming the perfect player.
“Alli is thriving in the free role given to him by Spurs boss Mauricio Pochettino.
“Last season he scored all but one of his goals with his right foot, now he is showing his full range of attributes. I love his footballing arrogance.
“Alli knows how good he is and, if he does not leave England he has the ability to become the best attacking midfielder in Premier League history.”
At just 20 years of age, Alli’s efforts are made all the more remarkable by the fact that he is in just his second full Premier League campaign, with League One outings at Mk Dons being taken in until the end of the 2014-15 season.