He made his first team debut the following year against rivals Manchester United at Old Trafford. With the Reds 2–0 up in the 81st minute Shankly took off John Toshack, replacing him with the 18-year-old defender. The move was intended to tighten up the defence and keep a clean-sheet, but three minutes later, Emlyn Hughes popped up with a goal for Liverpool, with the game ending this way. In 1973, Liverpool won a double haul of trophies—the League championship and UEFA Cup and Thompson played a role in both successes earning league and UEFA Cup medals in the process. The next season led to him displacing Larry Lloyd from the side altogether and pushed Tommy Smith across to full back, and he settled into a defensive partnership with club captain Hughes.