Sir Alex Ferguson's smile as he hinted Wayne Rooney could yet talk his way onto the Manchester United bench for Wednesday's Champions League clash with Bayern Munich may have been designed to lure opposite number Louis van Gaal into a corridor of uncertainly.

Van Gaal and his team do not scare easily, however. Indeed, Bayern president Uli Hoeness insists they arrive at Old Trafford for the second leg of their quarter-final tie on "a tailwind" after Saturday's victory at title rivals Schalke 04 sent them back to the top of the Bundesliga.

In contrast, United have had the tables turned on them since a lead held for 75 minutes in the Allianz Arena was stripped away by two late goals, giving Bayern a slender advantage to protect at what is sure to be a thunderous Old Trafford on Wednesday.

While United, without the injured Rooney, were losing their Premier League lead to Chelsea, Bayern left Gelsenkirchen accompanied by an unrepentant orgy of self-congratulation that was not exactly well-received.

United, by Van Gaal's own admission, remain favourites to go through to the semi-finals thanks to Rooney's early goal in Germany. But Ferguson, who talked up the team ethic as a counter to the absence of his outstanding player, knows United must be better than they were against Bayern and Chelsea if they are to stay on course for a third successive Champions League final.

Ferguson could have been handed more difficult draws in the last eight, but Bayern's deserved victory at the Allianz and their ominous habit of getting the results they require make it clear United could have had it much easier.

And they will need to raise themselves from the dip in form and confidence they have suffered in the last week if they are to dent the supreme self-belief Bayern have carried with them from Germany.
Bayern's in-built resilience is allied to a danger on the break, typified by the width and pace provided by Franck Ribery and, if fit, Arjen Robben. United must therefore couple caution with their natural attacking intent.

Central to their quest will be Dimitar Berbatov, assuming Ferguson presents the enigmatic Bulgarian striker with another opportunity to silence the cynics after his performance in defeat against Chelsea brought more criticism.

Berbatov's perceived lack of mobility and unwillingness to run the channels, never his game anyway, drew some harsh words, but he is not and never will be Rooney. It is also worth nothing that some intelligent runs went ignored on Saturday as he was left in isolation for too long.

There is, however, no escaping the responsibility and expectation on Berbatov if he plays on Wednesday. He can ill-afford to spearhead another misfiring United display.

If United, as they insist, are able to cope without Rooney, they must present a more convincing case against Bayern than they did at any time against Chelsea.

Ferguson will hope tired legs were at the root of United's lethargy at the weekend, when even Didier Drogba's blatantly offside winner should not be allowed to disguise their inferiority to Carlo Ancelotti's side.

And United must play the game at the high pace that suits them, although much of that tempo is usually set by Rooney. Ferguson's default position as a tactician is a cavalier, attacking one, and his side went too easily into retreat in the first leg, almost inviting the calamity that befell them in the closing minutes.

Their cause will be helped if they can rediscover the passing accuracy that has also mysteriously deserted them in their last two games. Ferguson rightly regards possession as at least nine-tenths of football's law and it has been surrendered too easily to Bayern and Chelsea, opponents only too willing to accept this uncharacteristic generosity.

United, though, are too good a side for this to continue unchecked, and Darren Fletcher will once again be a vital figure, a player Ferguson counts on to set the tone on nights like Wednesday.

Ferguson will also want to inject this extra pace into his side to unsettle Bayern, and his love of natural width may mean this is a big night for the maturing Antonio Valencia and Nani

United will find it easier to adopt their more traditional attacking stance with Old Trafford behind them - forget the jibes about the long silences and prawn sandwiches because the place can rock with the best of them on Champions League nights.

Pace, passing and power, plus a clean sheet, will be at the heart of United's approach. And the good news is that Ferguson's
players have proved more than capable of dealing in all of these precious commodities on countless occasions in the past.

Ferguson may also wish to focus on the potentially premature triumphalism of Bayern's Mark van Bommel, who painted a bleak picture of United's prospects - always a dangerous tactic from any opponent preparing to visit Old Trafford.

After his side's win in the first leg, the battle-hardened Netherlands midfielder claimed: "I saw the look on the faces of the United players and they were in a state of shock and anger. It was like they couldn't believe what we had done to them, and I'm sure that will have had an impact on them psychologically."

Van Bommel might be guilty of over-doing the optimism. Ferguson has an extra glint of steel in his eye when presented with an uphill challenge at Old Trafford - he almost revels in the notion of United making life difficult for themselves before escaping unscathed.

It will be another of those nights as United attempt to avoid a miserable conclusion to the most testing week of their season.