 Complete the following phrase:  During the early 1970s Manchester United were no longer competing among the top teams in England, and at several stages were battling against relegation. At times, Charlton was not on speaking terms with Uniteds other superstars George Best and Denis Law, and Best refused to play in Charltons testimonial match against Celtic, saying that to do so would be hypocritical. Charlton left Manchester United at the end of the 197273 season, having scored 249 goals and set a club record of 758 appearances, a record which Ryan Giggs broke in the 