It is undoubtedly the tie of the round, but tomorrow's meeting between Chelsea and Manchester United at Stamford Bridge is likely to mark the end of the London club's hopes of winning a major domestic trophy this year.

Ruud Gullit's team have played some wonderful football this season and have become a favourite side for neutrals, but even before they started to wobble a couple of weeks ago, they have always had weaknesses in key areas and United should be well able to exploit them.

The fact that United seem increasingly certain to retain their Premiership title will add bite to the tie, as it will to the whole competition. Chelsea will be desperate to pick up a trophy this season, but unless they can produce the sort of performance which stunned Liverpool in the fourth round last year, they will have to hope that they fulfill their ambitions either in Europe or the League Cup.

Defence remains the main problem for Gullit. Although Michael Duberry and Frank Leboeuf look solid when at their best, everything starts to look pretty shaky when either of them are absent or off-form. More worrying, however, is Frank Sinclair, who stands out as the team's greatest liability.

In a team which passes the ball so well, Sinclair's continued inclusion is remarkable. He is not a good distributor and other teams have come to realise that if they can isolate him, then they will be regularly rewarded with possession in dangerous areas of the pitch.

The problem is that there is no obvious replacement for the 26-year-old: Dan Petrescu is playing well in midfield, Steve Clarke no longer really possesses the pace for full back, and Paul Hughes, who had a stint in the position earlier in the season, has struggled to cope there, too.

In attack, too, the Cup holders have their limitations, primarily a lack of width which tends to restrict their options against teams determined not to be broken down.

We've seen this a few times in recent weeks, particularly in the games with Leeds and Wimbledon, when the standard ploy of playing the ball to Zola around the area and allowing him to pick the best route to goal let them down. While United have Giggs - or the option of playing Beckham out wide - Chelsea generally have to keep plugging away through the centre. If their opponents can hold their nerve, it tends to be only a matter of time before Gullit's men become frustrated.

United, on the other hand, have all the options a manager could ask for - and then some. At the moment they are winning the Premiership with several players - Denis Irwin, David May, Jordi Cruyff, Roy Keane etc - who would waltz into just about any other English team either laid up or unable to command a place.

Alex Ferguson is talking about adding to the squad in order to strengthen their challenge for the Champions' League, but the fact that the younger players have matured so well over the past couple of years has greatly increased competition for places already while the return to form of Andy Cole has removed the pressure to bring in another striker. With such depth, Ferguson possesses an answer to just about every question that is asked of him.

The return of Irwin and Schmeichel for this game will be a boost for the visitors, but the form of Beckham, who is the best long passer of the ball around at the moment, will be even more important, while the strength of their midfield should be enough to disrupt Chelsea's passing game.

If Gullit decides to play himself, then it will make the tie even more interesting, but Chelsea miss Gustavo Poyet in the centre of the field. The pace and ingenuity of United, who should have been shaken up slightly by the defeat at Coventry, should prove enough to see them through, even if it takes a second match to sort the tie out.

Elsewhere, there aren't too many matches that set the pulse racing. Liverpool are playing well at the moment and should be too strong for Coventry, while Arsenal, Leeds and Aston Villa should all come through without too much bother.

Blackburn's tie with Wigan - a club owned by Dave Whelan, an Irishman who used to play for Blackburn - should be a nice game, while the toughest one to call is Everton's clash with Newcastle. Everton's form in the league has been abysmal this year, but in the last couple of months Newcastle are actually the worst team in the division. While Everton know that they need Duncan Ferguson to perform if they are to thrive, the Newcastle faithful are not even sure who to look to anymore.

There seems to be nobody capable of scoring regularly for them and while Faustino Asprilla's return from injury has been a welcome boost for Kenny Dalglish, the Colombian still doesn't look fully match fit and seems incapable just yet of making the required difference.

Overall, though, the third round doesn't look likely to produce too many upsets, which should mean plenty of good teams in the hat for the fourth round when we might get quite a few interesting ties.

For the likes of Roy Evans, Arsene Wenger and Dalglish, men who will all see the Cup as their best chance of salvaging something memorable from the season, United's absence from that draw would be a very welcome late Christmas present. However, I can't help feeling that if they want Alex Ferguson's side out of the running, then one of the their teams is going to have to do the hard work themselves.

(In an interview with Emmet Malone)