THE VITAL BATTLES
We look at how each team can avoid their day turning into a nightmare.

STOPPING RONALDO AND ROONEY
Shutting down two players out of 11 seems simple. But such are the talents of Manchester United's two most precious assets that they are often unplayable. The good news for Chelsea is that neither has ever scored against them, thanks largely to the Blues' near-impenetrable defence. The bad news is that Rooney in particular reserves his best performances for the biggest games. As for Ronaldo, Chelsea will be particularly keen to have Ashley Cole available, with the England left-back enjoying an impressive record when pitted against the Portugal winger.

WINNING THE MIDFIELD BATTLE
There is a good reason why this is one of the biggest cliches in football and it will be no different at Wembley. United's midfield has been by far the most dynamic in the Premiership this season with Ronaldo, Ryan Giggs, Paul Scholes and Michael Carrick boasting a host of goals and assists for the Red Devils. Chelsea began the season with a midfield that placed the emphasis very much on strength and stability. Out went Arjen Robben, Damien Duff and Joe Cole, as the Blues battered opponents into submission. Cole's return from injury has resulted in a more fluid system but they may need to revert to a more muscular approach to nullify United's threat.

SAFE HANDS?
Such a high-profile game puts goalkeepers under the microscope like never before and the slightest mistake or moment of inspiration could make the difference between victory and defeat. Chelsea number one Petr Cech is widely regarded as the best in the business and it is no coincidence his return from a serious head injury has ushered in the Blues' four-pronged trophy assault. United counterpart Edwin van der Sar has finally helped fill the void left by the legendary Peter Schmeichel at Old Trafford, but high-profile mistakes against Roma and Portsmouth show he can be prone to the odd lapse in concentration.

BEWARE OF THE DROG
Didier Drogba has been the focal point of the Chelsea attack ever since he signed almost three years ago. Always a physical presence able to bring others into the game, this season has seen him emerge as one of the most feared goalscorers on the planet. He also proved he was the man for the big occasion with a match-winning performance in the Carling Cup final against Arsenal, meaning United must limit his influence at Wembley. However, with a defensive crisis on their hands, their ability to do that is very much open to question.

PAST BATTLES
We look at the 10 past encounters between the sides in this competition, from most recent to the very first.

March 10, 1999 - FA Cup quarter-final replay: Chelsea 0 Manchester United 2
A brace from Dwight Yorke, with one goal scored in each half, took United into the FA Cup semi-finals in their treble-winning season in a Stamford Bridge replay. The initial tie at Old Trafford on March 7 finished goalless, with Paul Scholes and Roberto di Matteo sent off.

January 4, 1998 - FA Cup third round: Chelsea 3 Manchester United 5
A bizarre tie which United led 5-0 with 74 minutes played after a brace apiece from David Beckham and Andy Cole and one more from Teddy Sheringham before Graeme Le Saux's goal and a double from Gianluca Vialli briefly raised the possibility of a comeback.
March 31, 1996 - FA Cup semi-final: Manchester United 2 Chelsea 1
United moved a step closer to an historic second domestic double with this semi-final win at Villa Park. Andy Cole and David Beckham scored the Red Devils' goals with Ruud Gullit grabbing the Chelsea reply.

May 14, 1994 - FA Cup final: Manchester United 4 Chelsea 0
Manchester United completed the domestic double for the first time in their history with a comfortable win. Two penalties in six minutes from Eric Cantona (60 and 66) and further goals from Mark Hughes and Brian McClair did the damage.

January 30, 1988 - FA Cup fourth round: Manchester United 2 Chelsea 0
Norman Whiteside and Brian McClair continued United's cup superiority over Chelsea, but they were eliminated in the next round by Arsenal.

January 15, 1979 - FA Cup third round: Manchester United 3 Chelsea 0
United made easy work of this tie with goals from Steve Coppell, Jimmy Greenhoff and Ashley Grimes at Old Trafford. Dave Sexton's team reached the cup final, this time losing to a late Alan Sunderland goal in a 3-2 defeat to Arsenal.

March 16, 1963 - FA Cup fifth round: Manchester United 2 Chelsea 1
This was the season where the United trio of Bobby Charlton, Denis Law and George Best came together for the first time, and the Red Devils went on from this tie to win the FA Cup, beating Leicester in the final. Albert Quixall and Law got the United goals, Dennis Sorrell replying for Chelsea.

March 4, 1950 - FA Cup quarter-final: Chelsea 2 Manchester United 0
Chelsea's only FA Cup victory over United, as Roy Bentley and Bobby Campbell scored for the Blues in front of a crowd of over 70,000 at Stamford Bridge.

February 1, 1908 - FA Cup second round: Manchester United 1 Chelsea 0
The first meeting of the sides was won by United thanks to a Sandy Turnbull goal at their old Bank Street ground. United finished the season by winning the league title for the first time in their history.



THE GAFFERS
How the two managers shape up...

PLAYING RECORD
Ferguson had a solid club career in Scotland, scoring 167 goals in 327 appearances. His most prolific spell came at Dunfermline where he netted 66 times in 88 appearances. He became the record Scottish signing when he moved to Rangers for £65,000 in 1967. (6/10)

Mourinho had a generally unsuccessful playing career at small clubs in Portugal. It was clear he was keen on a coaching role instead, as he regularly prepared match reports for his father's teams. (2/10)

COACHING CAREER
Ferguson is the most successful manager in English football history, winning more trophies than any other manager. The Scot began to make his mark in the managerial world when he was appointed boss at Aberdeen, picking up 10 trophies during his eight years at the club.

He was given the Manchester United job in 1986 on the back of his success in Scotland and although he struggled in his early days, he has gone on to pick up 18 major trophies, including the first ever treble by an English club. He is also the only manager to lead his team to three consecutive league championships in the English top flight. (9/10)

Mourinho has earned himself a reputation as one of the best managers in Europe as a result of his success with Porto and Chelsea. He won the treble of league, cup and UEFA cup in his first season in charge of Porto, followed by a league and Champions League double the following year.

Mourinho replaced Claudio Ranieri at Chelsea in 2004 and delivered the club's first league championship for 50 years in his debut season, as well as the League Cup. He retained the Premiership last season and won the league cup for a second time earlier this year. (8/10)

MAN MANAGEMENT
Ferguson is a strong advocate that no player is bigger than the club, evidenced most recently by David Beckham's move to Real Madrid in 2003 and Ruud van Nistelrooy's departure last season. Ferguson's "hairdryer" treatment in the dressing room is renowned and the hard disciplinary line he takes has been mentioned as one of the key factors behind United's success. (8/10)

Mourinho is famous for his self-belief and has been a controversial figure at times, claiming he was "the special one" on his arrival at Stamford Bridge. He is willing to make unpopular selection decisions and has regularly left Andriy Shevchenko, the club's record signing, on the bench. He has remained focused despite speculation of a rift with Roman Abramovich. (9/10)

TACTICS
Ferguson has always favoured free-flowing, attacking football. His use of wingers has caused teams problems for many years, never more so than this season when Cristiano Ronaldo and Ryan Giggs have terrorised opposition defences.

United's defence has also been strong this season, largely due to the sensational form of Nemanja Vidic in his second season at the club. With three of their attackers nominated for the PFA Player of the Year award and the defence keeping it tight at the other end, Ferguson has found the perfect balance. (9/10)

Mourinho prefers a more conservative approach. He packs the central midfield with quality in the hope of grinding teams down, a style that has been criticised by football purists but has proved to be very effective.

In Didier Drogba they have the Premiership's top goalscorer who has provided the firepower for much of their success. Petr Cech has been a fantastic last line of defence for the Blues and the combination of the two has made Chelsea a very difficult team to beat. (8/10)

JOB PROSPECTS
Ferguson endured calls for him to step down in recent years after a relative lack of success but has silenced the doubters with a stunning return to form this year. He is a hero among United fans and surely will stay at the club for as long he desires. (10/10)

Surprisingly, Chelsea's semi-final victory over Blackburn was greeted with comments by Mourinho expressing uncertainty over his future. After weeks of reports on a rift between Abramovich and Mourinho, the club insisted the manager would not be sacked but it would not be a surprise if he moved on. (7/10)

TOTALS
Ferguson 42/50
Mourinho 34/50