On 19 August 1989, a 37-year-old man walked on to the Old Trafford pitch before the first game of the new league campaign. Arsenal were the opposition, and the stands were packed; the official attendance was 47,245 - about 10,000 higher than the previous season's average. In full Manchester United training kit, Michael Knighton juggled the ball skillfully before firing it into an empty goal. He stood in front of the Stretford End, arms out, taking in the adulation. A few weeks before,