Real Madrid face a daunting task as they look to overturn a 4-1 deficit to Borussia Dortmund in the second leg of their Champions League semifinal, but the Spanish champions will know that Cristiano Ronaldo’s away goal last week gives them a chance of a famous comeback.

Observers were quick to parcel the result at the Westfalenstadion together with Bayern Munich’s 4-0 mauling of Barcelona as a sign of a shifting of power in Europe from Spain to Germany, but it is often dangerous to make such sweeping conclusions.

It is only three weeks since Dortmund were staring down the barrel of an exit from the quarterfinals as they required two goals in injury time to beat the side currently fifth in La Liga, Malaga. Jurgen Klopp’s men, of course, famously got those goals in a dramatic finale, but the performance that night should be a source of confidence to Madrid.

Dortmund were the heavy favorites to progress after a draw in Malaga but appeared to wilt somewhat under the pressure as they struggled to produce their usual free-flowing game.

The Bundesliga side will, of course, be in the position of being even more fancied to make the next round on Tuesday. For all their undoubted quality, Dortmund are a young side full of players with no prior experience at this stage of the Champions League.

If Madrid get a good start and ideally an early goal then the atmosphere in the Bernabeu will crank up dramatically and serious questions will be asked of Dortmund’s mental toughness.

One does not have to look hard to find examples of the strength of momentum in two-legged ties and how doubts can quickly set in for a team with a significant first-leg lead. Both European competitions this season has littered with such ties.

In the Champions League round-of-16, Bayern Munich were expected to progress at a canter after winning 3-1 at Arsenal in the first leg. But, not sure whether to stick or twist, Bayern were hamstrung back at home and Arsenal fell just a goal short of going through.

At the same stage of the Europa League there was an even more dramatic example when Tottenham beat Inter Milan 3-0 at home before losing by the same scoreline away and only squeezing through after extra time.

Even Real Madrid will be aware of how such a reversal of fortunes can occur. In the quarterfinals Galatasaray trailed Madrid 4-0 on aggregate before coming back to 4-3 and, albeit briefly, giving Mourinho’s men a fright.

What is also true, of course, is that Madrid will have to up their performance significantly from the one that enabled Dortmund to tear them apart at stages in Germany.

At the start of both halves that night Madrid appeared unprepared for the incredible energy that Dortmund displayed both on and off the ball and unable to deal with the onslaught of the wave of yellow and black shirts.

If Dortmund are able to play with that intensity again in Spain, then Madrid have to do a far better job of matching it and using the greater experience to ensure that the match is played on their terms. To do that it will require every player to be on the same page and fully focused on the job at hand, something which Madrid’s reportedly fractious dressing room has been accused of failing to do at various points this season.

Jose Mourinho, who has -- perhaps for the first time in his managerial career -- struggled to engineer a fierce unity between himself and his squad, has said that the match is the club’s biggest in 10 years. With the Portuguese almost certain to leave Madrid at the end of the season whatever happens in its remaining weeks, it is also a match that could well define his three years in charge of Europe’s most gloried club.

With a three-goal margin Dortmund should progress to end Madrid’s hopes for another season of La Decima, but it is far from the foregone conclusion that many have suggested.