The 'Class of 92' graduate had played what seemed to be his final game for the Red Devils the previous May at Wembley in the Champions League final defeat by Barcelona.
Scholes called time on his career at the age of 36 and joined the club's coaching staff, but Sir Alex Ferguson convinced the midfielder to reverse his decision during an injury crisis at Old Trafford.
With Darren Fletcher and Tom Cleverley long-term absentees, the return of the United great was announced an hour before kick-off at the Etihad Stadium when he was listed among the substitutes for the third-round tie.
Ferguson introduced Scholes in the 59th minute for his 677th appearance for the club and while he was slightly off the pace against City, he still played a part in helping them clinch a thrilling 3-2 victory.
The midfielder would add another goal to his tally in the next match against Bolton in the Premier League and scored a further three times to end the campaign with four goals from 21 appearances.
It convinced Ferguson and the club to offer Scholes a one-year contract, which he accepted and he bowed out alongside the long-serving United boss on May 19, 2013 after a 5-5 draw at West Brom, with another title secured.
That outing at the Hawthorns was not his last in football, however, with the 66-cap England international again coming out of retirement five years later to play for Royton Town of the Manchester Football League Premier Division.
Before that fleeting return for his son Arron's team, Scholes purchased Salford alongside fellow 'Class of 92' members Gary and Phil Neville, Ryan Giggs and Nicky Butt in 2014 and he remains joint-owner of the now Sky Bet League Two side.
The 11-time Premier League winner has also had brief managerial stints since he retired from the professional game, spending a month in charge of Oldham in 2019 and having two spells as Salford caretaker while they searched for a new manager in 2015 and 2020 respectively.