By Stuart Roach

Ferguson faces the music following Man Utd's Champions League exit

In the blur of Wednesday's remarkable match with Real Madrid, it was not always easy to spot where Manchester United's problems lie.

It's like asking a Formula One pit mechanic to assess the problems on a car mid-lap.

But when this rollercoaster season finally shuts down for the summer, Sir Alex Ferguson will need to take stock of his shell-shocked squad.

It would be churlish to pick holes in United on the back of Ronaldo and co doing just that over two remarkable quarter-final legs.

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But failure to snatch back the Premiership crown from Arsenal would consign United to a second trophyless season.

Captain Roy Keane says United must learn from the lessons handed out by the best team in the world, so where can Ferguson improve his class of 2003?

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Here, BBC Sport considers those lessons and delivers a mid-term report:

Goalkeeper:

Barthez: Injury prone and highly unpredictable

Other than Peter Schmeichel, signing goalkeepers has proved one of Ferguson's biggest headaches.

Although a major improvement on Massimo Taibi and Mark Bosnich, Fabien Barthez has hardly provided the cure for Ferguson's problem.

At his best, brilliant, at his worst a liability, Barthez is also painfully injury prone. Saturday's win over Blackburn saw him hobble off for the ninth time in his United career, a worrying statistic for Ferguson to digest.

Beaten at his near post by Ronaldo for the crucial opening goal on Wednesday, though stood no chance with either of the Brazilian's other goals.

Verdict: Erratic stopper will leave in the summer if Ferguson can finally find a suitable replacement.

Defence:

Ferdinand: Beaten for pace by Ronaldo

The case for the defence comes with mitigating circumstances considering United were facing the most potent attacking force in world football.

But serious cracks remain that Ferguson cannot merely paper over.

Personnel is probably not the problem, but consistency is the key, with Ferguson still unconvinced as to what his best defence is.

The back four he fielded on Wednesday is arguably the one to stick with. John O'Shea should be rewarded with the PFA young player of the year award and Wes Brown is growing in stature as a full-back.

Conversely, Mikael Silvestre looks ultimately happier at the heart of United's defence, where his pace sits nicely alongside Rio Ferdinand's class.

But, worryingly, the world's most expensive defender was woefully outpaced by the world's deadliest striker as Ronaldo claimed his vital opener and chasing the game meant United's quartet was increasingly pulled wide and ragged as the game wore on.

Verdict: Ferguson will have one eye on a new full-back, but consistency remains the key.

Midfield:

Beckham: Facing a sad exit?

Two years ago, no-one in their right mind would have questioned United's midfield.

But two quarter-final collisions with Real Madrid's dream team exposed some real problems.

Roy Keane, for so long the heartbeat of United, is a shadow of his former self, while the driving force was left in transit.

David Beckham's exile to the substitutes' bench may be a precursor to a summer departure, but if Ferguson's palms are itching at the prospect of a �25m windfall then he has seriously undervalued the England captain's true worth to his team.

More pressing is solving the problem of the post-op Keane who, at the very highest level on Wednesday, was found wanting.

Paul Scholes was conspicuous by his absence through suspension and remains one of Europe's most respected attacking midfielders.

And cashing in on Ryan Giggs' returning form may, like any Beckham sale, create more problems than it would solve.

One more controversial source of income is Ole Gunnar Solskjaer, who remains a misfit in Ferguson's first-team jigsaw.

A natural striker, Solskjaer has enjoyed a fine run of form on the right of midfield, but to the detriment of Beckham, whose continued absence hints ever more strongly at a summer exit.

Ferguson knows the Norwegian would shake off his supersub tag at any other Premiership club and would generate enough money to aid Ferguson's rebuilding programme.

Verdict: Old Trafford engine room is in serious need of attention.

Strikers:

Van Nistelrooy: Goals have carried United

Ferguson discovered an absolute gem in Ruud van Nistelrooy and his determination to sign the Dutchman following a serious knee injury has been hugely vindicated.

But Ferguson will be desperate to find a foil for his top striker, who scored in every round of United's latest Champions League campaign.

Solskjaer has always had to play second fiddle since Van Nistelrooy's arrival and Diego Forlan still has some way to travel before fulfilling the potential Ferguson saw in him.

Giggs has rediscovered his goal touch with 15 goals but he and Scholes remain awkward partners for Van Nistelrooy, whose remarkable 41-goal haul this season has kept United in the hunt for honours.

Verdict: Lonely heart Van Nistelrooy seeking the ideal partner.

Ferguson: Remains upbeat despite Man Utd's flaws

Manager:

Sir Alex Ferguson must sometimes wonder whether he did the right thing in changing his retirement plans.

Failure to hold off Arsenal in the title run-in will leave the manager without a trophy from two frustrating seasons.

But Ferguson remains the finest British manager of the modern era and will be determined to pull off one more coup before he finally steps down.

Verdict: Ferguson needs to freshen up at Old Trafford. Beckham's departure looks increasingly likely and would fund his rebuilding - but at what cost?