Let’s go back 21 years. Manchester United were going head-to-head with Real Madrid at Old Trafford in a titanic Champions League battle. A hat-trick from Brazil’s Ronaldo was enough to see Real qualify on aggregate, but Manchester United had gone out swinging, defeated the star-studded side 4-3 at Old Trafford. It was an unforgettable match, but soon afterwards, one of United’s stars was signing for Real, with David Beckham later revealing that Zinedine Zidane tried to talk him into a move at the final whistle. Beckham’s exit came as Real’s Galactico era was really taking off. Since then, it’s…