Sir Alex Ferguson
Sir Alex Ferguson knows that he is running out of time to add to his two Champions League victories with Manchester United. Reuters

Each of the Champions League last-16 ties have their appeal, but there can be no doubt that the contest between Real Madrid and Manchester United is the true heavyweight matchup of the round. Even ignoring the fact that it features arguably the two biggest clubs in the world, the subplots alone make the two legs a tantalizing prospect.

Sure, there is Cristiano Ronaldo taking on former club for the first time as a Madrid player, but most intriguing is the clash between the two managers, who have a rich history and potentially intriguing future relationship.

Sir Alex Ferguson and Jose Mourinho first met when the young upstart Portuguese was the subject of a burst of Ferguson’s rage after what he believed to be Porto’s theatrics in their Champions League last-16 tie back in 2004. In the second-leg back at Old Trafford, Porto stunningly knocked out United and Mourinho announced himself on the European stage by charging down the touchline to celebrate with his players.

Despite Mourinho initially getting the better of Ferguson again when the Portuguese manager moved to England with Chelsea, the two have since developed an unlikely friendship.

The two share not only a love of fine wine but an undoubted often ruthless desire to win. Such is Ferguson’s respect for Mournho that he has even suggested that the Madrid manager would make a fitting replacement when he finally steps down at United.

Regardless of whether it is to step into Ferguson’s shoes, Mourinho looks almost certain to depart Madrid at the end of the season. Yet, if he does so without winning the Champions League then he will surely consider his time at the Bernabeu a failure, despite claiming the Liga title last season.

Mourinho loves records and he is desperate to be the first coach to win the European Cup with three different clubs and do it by giving the competition’s most successful team their 10th trophy. It has been a tumultuous season at the Bernabeu with almost constant reports of rifts between certain players and the coach, but all will be forgotten and Mourinho can depart a legend if he lifts that giant trophy in May.

Despite his almost three decades of success at United, Ferguson too is eager to enshrine his legacy in Europe’s premier competition. The Scot has repeatedly expressed the opinion over the years that Manchester United should have won more Champions Leagues in his time in charge than the two triumphs, in 1999 and 2008.

And Real Madrid have played a huge part in United’s failure to establish a period of dominance in the competition.

Ferguson has established a reputation as a coach of consistently attack-minded teams at Old Trafford. Certainly the side that won the competition in 1999 were just that. Their route to the trophy was littered with epic matches and a prevailing attitude of, no matter how many goals the opposition scored, they would get one more.

But Ferguson’s tactics were dramatically altered in Europe the following year when Madrid came to Old Trafford in the second leg of their quarterfinal having drawn the opening encounter 0-0 in Spain. Madrid stunned the defending champions with a 3-2 win that exposed the Premier League side’s naivety as the Spaniards went onto claim two titles in three seasons.

The following campaign Ferguson set his side up with an extra man in midfield and a "safety first" approach, particularly away from home, and it has been that way ever since. Until, perhaps, now.

The signing of Robin van Persie last summer raised eyebrows aplenty. It was clear to most that what United needed most was a strong midfield presence, rather than another striker to join Wayne Rooney, Javier Hernandez and Danny Welbeck.

Van Persie, perhaps unsurprisingly, hit the ground running and he has also embodied United’s renewed gung-ho attitude this season. Particularly early on in the campaign, United often went behind, rarely looked in control of matches, yet continued to win.

It raises the intriguing question of whether Ferguson will continue to opt for an attack-minded lineup featuring Van Persie supported by Rooney against a side as devastating on the counter attack as Real Madrid.

In some ways it would be foolish to do so, but Ferguson may see it at his side playing to their strengths, rather than relying on an often suspect looking defense.

At least at the Bernabeu, it is hard to imagine Ferguson not taking steps to try and mitigate Madrid’s threat and particularly that presented by his former charge Ronaldo. Phil Jones may well be given the nod in a right-sided defensive midfield slot to help out Rafael against Ronaldo as the versatile youngster recently did successfully against Gareth Bale for Tottenham.

However Ferguson sets up his side, it is likely to be crucial to the outcome to this most mouth-watering of ties, with the battle between the two men on the touchline as captivating as any of those between the litany of stars on the pitch.

The first-leg of the Champions League last-16 tie can be watched on the Fox Soccer Channel from 2.45 p.m. ET on February 13. In the U.K. the match will be screened live on Sky Sports 2.