Their decision was to appoint from within, by promoting one of Busby's coaches and former players, Wilf McGuinness, to the senior position. A combination of ageing stars and the lack of overall control in team affairs meant that McGuinness struggled to impose his authority. Putting popular figures like Denis Law and Shay Brennan on the transfer list didn't help matters, neither did George Best's distracting off-field behaviour. Wilf wasn't allowed to struggle for too long. On Boxing Day 1970, he was relieved of his duties and Sir Matt was put back in temporary charge. Frank O'Farrell was the next man to take over in June 1971 but, despite a promising start, United's 5-0 defeat by Crystal Palace on 16 December 1972 was the Irishman's last match in charge. Although O'Farrell's tenure was short, he still left his mark by signing Martin Buchan for a record fee of £125,000. The former Aberdeen captain was to become a key player for O'Farrell's successor, Tommy Docherty, who was appointed around Christmas in 1972. The Doc's first challenge was to keep the team in the top flight, while gradually replacing the legends of the 1960s. Bobby Charlton had announced he would retire at the end of the 1972/73 season, Best was frequently veering off the rails once again and Law had passed his peak. Law, in fact, was given a free transfer in July 1973, a move which later came back to haunt Docherty. The striker joined Manchester City and scored at Old Trafford in April 1974, on a day when United's relegation to the Second Division was confirmed. To Docherty's credit, the Reds bounced back very quickly. They won the Second Division championship in style in 1974/75, with top scorer Stuart 'Pancho' Pearson contributing 17 league goals. Lou Macari scored the goal that clinched promotion, at Southampton on 5 April 1975. United then reached successive FA Cup finals, losing to Southampton in 1976, but beating Liverpool 2-1 a year later. The Doc's men rose perfectly to the task of destroying Liverpool's Treble hopes – the Merseyside club won the League Championship and the European Cup on either side of United's triumph. The joy of that win didn't last very long for the Doc, however. Just 44 days later, he was sacked following off-field revelations. QPR manager Dave Sexton stepped into the breach, and although he finished no higher than 10th in the table in his first two seasons 1977/78 and 1978/79, he again guided the side to Wembley in 1979. Unfortunately the Reds lost there, 3-2 to Arsenal in one of the most memorable finishes to an FA Cup final. Gordon McQueen and Sammy McIlroy scored in the last five minutes to bring United back from 2-0 down, only for Alan Sunderland to grab Arsenal's winner on the brink of extra-time. Those frenetic last few moments at Wembley summed up the 1970s for United, a decade of high drama when great highs and lows were never far apart.
With memories of European Cup success beginning to fade, Manchester United's attentions turned to their managerial vacancy in a decade of high drama.
Sir Matt Busby had led the club to the promised land but had now retired, leaving big boots to fill – a search that would influence some great highs and deep lows.