Age can be just a number. It can also be a significant one. "There is no chance I will be 40-something again," said Mourinho a couple of weeks ago, in a reflective mood. "We cannot stop time."

At 55, Mourinho is in the second half of his managerial career; perhaps one who started at 37 has been for some time. Yet United are proof that is not necessarily a bad thing. Their three European Cups were secured by Sir Matt Busby (then 59) and Sir Alex Ferguson (at 57 and 66). Ferguson was 69 in his last Champions League final. After turning 55, he won the Premier League 10 times.

The problem with comparing anyone with Ferguson, however, is that he can be the exception to most rules: his long-term adversary Arsene Wenger has no league titles since his 55th birthday, for instance. And while another great anomaly, Bob Paisley, did not start a managerial career that yielded six league titles and three European Cups until he was 55, Liverpool's most successful leader conforms to one trend: the majority of even the most decorated coaches have around a decade when they seem at the peak of their powers. Once again, Ferguson may be the odd man out.

Mourinho's managerial career can be divided neatly into five-year periods. Between his 40th and 45th birthdays, the Portuguese won four league titles, the Champions League and the UEFA Cup. Between his 45th and 50th, he secured a further three league titles and a second Champions League. Since reaching 50, he has won one more domestic league and the Europa League. Taken in isolation, ignoring context and circumstance, it suggests Mourinho is in decline.

If his trophy-laden past gives him a cast-iron case to greatness, there is the sense that he is searching for a defining achievement in the latter period of his career, whether becoming the first manager to win the Champions League with three different clubs or the first since Ferguson to make United champions of England. He might even have to be a man out of time if he is to accomplish the former.

Conquering Europe is a comparatively young manager's game. Since the 71-year-old Raymond Goethals triumphed with Marseille in 1993, only two managers over the age of 55 have won the Champions League: Ferguson (twice) and the 68-year-old Jupp Heynckes in 2013. It marks a change: including Busby and Paisley, the European Cup was clinched nine times by a manager who had celebrated his 55th birthday between 1961 and 1984 including Helenio Herrera, who claimed to be born in 1916 but is believed to be six years older, and was thus not actually 49 when Inter Milan prevailed in 1965.

The facts suggest it is now easier to realise in ambitions in England than Europe at a relatively advanced age. Three of the past five Premier League titles have gone to managers aged at least 60; another was secured by Mourinho, aged 52 at the time. The past four FA Cups have all been won by managers in their 60s, generally Wenger; only five of the past 17 have gone to those under 50. Five of the past nine League Cups have been lifted by managers over 55, plus two more that went Mourinho's way at the age of 52 and 54.

Yet it is notable that after a period when there were plenty of sexagenarians and septuagenarians (Ferguson, Harry Redknapp, Roy Hodgson, Kenny Dalglish, Manuel Pellegrini, Louis van Gaal, Guus Hiddink) at major English clubs, now Mourinho is the second-oldest man in charge of a top-six outfit, behind only Wenger. Time can move on.

Many of those at the summit of the game in recent years have been Mourinho's juniors: Pep Guardiola, Antonio Conte, Zinedine Zidane, Jurgen Klopp, Massimiliano Allegri, Diego Simeone, Mauricio Pochettino and Luis Enrique are all within a decade of the United manager but at least four years younger. His contemporaries really include coaches like Rafa Benitez, Roberto Mancini and Frank Rijkaard who, for different reasons, are not challenging for major honours anymore.

The generation game may be reflected in styles of football. One recurring question is if Mourinho's brand of football was at his most pertinent and potent in the 2000s, not the 2010s, before emphasis on pressing and passing emerged as a reaction to the defensively sound counterattacking he espoused. That said, Maurizio Sarri's Napoli exude modernity, and he is 59. The perennial Heynckes is back at Bayern Munich again and Mourinho remains younger than Carlo Ancelotti; the facts may not be in his favour in his quest to lift the Champions League again, but it would be rash to dismiss him as yesterday's man. Not in Britain and not on a global stage, either.

Mourinho has voiced an ambition to take charge of Portugal, who won Euro 2016 when Fernando Santos was 61, before he retires. Two of the past three World Cup-winning managers, Marcello Lippi and Vicente del Bosque, were over 55. Both, like him, won the Champions League at a younger age. If recent history suggests it is unlikely Mourinho will triumph in Europe again, England and the international game may offer more encouragement of a crowning glory.