By Alex Trickett

Sir Alex Ferguson marked his 1,000th game in charge of Manchester United safe in the knowledge that his legacy as one of the greatest managers in history is secure.

But it was not always that way.

Full story: Ferguson at 1000 Hansen's view: "Incredible"

Drawing on your thoughts on the 606 messageboards and on expert views, BBC Sport reflects on six key episodes in Ferguson's Old Trafford career.

Bryan Robson (left) and Alex Ferguson after the 1990 FA Cup win

It hardly seems plausible now, but Ferguson was perilously close to losing his job at the start of the 1990s.

He had enjoyed only limited success at Manchester United since taking over in 1986 and had seen his charges crumble to a limp 5-1 loss to neighbours City three years later.

Many believe a defeat to Nottingham Forest in the third-round of the 1990 FA Cup would have ended his Old Trafford reign.

Mark Robins saved Fergie's skin From Makaveli Don Killuminati Have your say on 606

Ferguson survived thanks to unlikely hero Mark Robins, whose goal settled that tie.

And United went on to lift the trophy courtesy of even-more-unlikely hero Lee Martin, who won a final replay against Crystal Palace.

If the Cup final win staved off the critics, United's subsequent Cup Winners' Cup victory announced the club's return to Europe's top table.

This time, Mark Hughes did the honours, scoring twice against former club Barcelona in a 2-1 win in Rotterdam.

Name: Eric Cantona Man Utd appearances: 190 Man Utd goals: 88

The pieces were starting to fall into place for Ferguson.

But the picture was not complete until the Scot pulled off arguably the biggest transfer coup of the decade by signing Eric Cantona for �1.2m from defending Division One champions Leeds.

The Elland Road club had pipped Manchester United to the title in 1992.

But Ferguson's Reds became unstoppable when they added "King" Cantona's creative flair to a team that already included Hughes, Bryan Robson, Ryan Giggs and defensive rocks Peter Schmeichel, Steve Bruce and Gary Pallister.

One of the most enduring images was when Bruce scored two late goals against Wednesday and Fergie leapt on to the pitch - class From O'Shea the Nutmegger Have your say on 606

Ferguson became untouchable at Old Trafford when he brought the club their first league title since 1967.

And he did so in style, landing the inaugural Premiership by 10 points from Aston Villa.

Central defender Bruce, unsung hero for so long, rose to the fore with his team trailing 1-0 to Sheffield Wednesday.

He scored an equaliser and then a second seven minutes into injury time to virtually win the league, sparking scenes of manic celebration as Ferguson and assistant Brian Kidd ran on to the pitch.

MAN UTD V ARSENAL INCIDENTS 1990: Arsenal docked points after brawl 1998: Marc Overmars sets up Arsenal title at Old Trafford 1999: Ryan Giggs' wonder goal keeps Man Utd on for treble 2001: Man Utd thump Arsenal 6-1 en route to championship 2002: Sylvain Wiltord clinches title for Gunners in Manchester 2003: Both sides criticised after stormy 0-0 2004: Ferguson is reportedly pelted with food

Less of an episode and more of a long-running saga, one of the most consistent features of Ferguson's reign has been an unflagging and often bitter rivalry with Arsenal.

Trouble flared up first in 1990, when the Londoners were docked �50,000 and two points for their part in a brawl at Old Trafford.

And tempers boiled over again when Arsene Wenger took charge at Highbury in 1996, sparking a catalogue of "mind games" with Ferguson.

Both managers have had their victories over the years, none tasting sweeter to Ferguson than the 1999 FA Cup semi-final win - inspired by Giggs' sensational solo goal - that kept alive his dream of winning the treble.

But the pressure is now on Ferguson and Wenger to cool the rivalry a tad before it spirals out of control.

Winning the Champions League and completing the real treble From Ice Ice Andy - No. 8 Have your say on 606

With a domestic double already under his belt, Ferguson looked set for the biggest disappointment of his career when United went 1-0 down to Bayern Munich in the Champions League final.

But a drab encounter finally sparked to life in injury time.

First, Teddy Sheringham slotted home from six yards and then David Beckham swung in a corner, which Sheringham flicked on for substitute Ole Gunnar Solskjaer to score.