London - Sir Alex Ferguson celebrates 25 years in charge of Manchester United on Sunday, undaunted by the possibility that the greatest challenges of an extraordinary career may yet lie ahead of him.
When Ferguson joined joined United from Aberdeen on November 6, 1986, the club were languishing 19th in the table out of 22 teams and had also been bombed out of the League club by Southampton.
In the quarter of a century since his arrival at Old Trafford, Ferguson has transformed United into the most successful side in English history, a reign that has included two European Cups, 12 League titles, five FA Cups, four League Cups and the World Club Cup.
Yet as English football reflects on Ferguson's achievements this weekend, the 69-year-old Scot will no doubt have his steely gaze firmly fixed on the twin challenges facing him at home and abroad.
A 6-1 home thrashing by Manchester City last month - described by Ferguson as "the worst of my career" - provided resounding evidence that United's cross-town rivals are fast evolving as the biggest threat to his reign.
And the 3-1 masterclass dished out by Barcelona to United in May's Champions League final at Wembley was a brutal demonstration of the level Ferguson's team must attain if they are to conquer Europe again any time soon.
Ferguson, however, has made a habit of staring down challenges to United's authority, having successfully repelled various incarnations of Arsene Wenger's Arsenal and the billionaire-backed nouveaux riches of Chelsea.
According to Ryan Giggs, Ferguson is showing no signs that his competitive fire may be flaming out as he approaches his 70th birthday.
"He's always first in at the training ground and last to leave, and he wants to see that kind of mentality from his players as well," Giggs said recently.
"He just loves his job. He loves watching United play. He loves seeing players develop. He loves everything about his job. You couldn't do what he does at his age and have the work ethic he's got if you didn't love it.
"We might have got home from a European away game at four in the morning, yet you can pretty much guarantee he'll be first in at Carrington at 8am the next day - and will be last to leave.
"You'll then stick the TV on later that night and see him at a function in London. It's unbelievable."
Bryan Robson, the former United captain, is similarly in awe of Ferguson.
"Everybody knows the work Sir Alex puts in around the club," said Robson. "They know about his teams, the trophies, the media, buying and selling of players.
"The most amazing part for me is that he still goes to a million functions. There are times when you cannot believe he is there.
"He might have three of the most important games of the season coming up in that week but he is at three of the functions you have been at.
"At his age, you think he should be tucked up in bed so he can concentrate on the football."
Steve Bruce, a key member of Ferguson's first title-winning side in 1993, is in no doubt about his former boss's position in the pantheon.
"In my opinion, he’s the best there's ever been. I know you can compare him to the (Bill) Shanklys and (Brian) Cloughs, but look at what he’s done and achieved," Bruce said.
"To still be doing it after 25 years is quite unbelievable ... He’s still fighting the world 25 years on and he thrives on it."
According to Robson, the secret of Ferguson's success has been to master the art of renewal - both of his team and his own competitive streak.
"It is impossible to win what he has without being able to renew yourself and the biggest trick is that he doesn't let people around him lose their hunger either," Robson said.
The United manager's determination to tackle adversity head on could be seen in his programme notes for Wednesday's Champions League match with Otelul Galati, where Ferguson admitted the sting of City's drubbing was still felt.
But in Ferguson's view "there is no progress in life without failure".
"For one thing, it means you think about how you got to the top in the first place," Ferguson wrote.
"It's another day in our history, one that will be talked about for a long time to come. We have certainly had better days, but there is no time for tears.
"Our players are eager not to make that kind of mistake again - or at least not for a very long time."