Champions League predictions - Chelsea will crash out if they don't try and score against Barcelona in Camp Nou
When Barcelona walked into Stamford Bridge a week ago for their Champions League semi-final first leg against Chelsea, the Catalan giants were on a run of 14 wins and one draw from their last 15.
The portents for Roberto Di Matteo's side looked bleak. It wasn't going to be a case of if Chelsea would lose - it was how many they were going to concede.
But whether through spectacular fortune or tactical mastery, the Londoner's famous victory that night has changed the picture considerably. Not just because their 1-0 victory puts them in a good position to squeeze through to the final, but because it seems to have sent Barca into something of a spin.
Now Pep Guardiola's side welcome the Blues to Camp Nou for their semi-final second leg after two straight defeats. Real Madrid's shocking win against their eternal rivals in Catalonia on Saturday all but confirmed Barca as runners up in the La Liga title race this season.
The victory is the first for Jose Mourinho against the Catalan giants in ten attempts. But what is more pertinent for the Blues is that it was a victory earned at the Nou Camp.
Now, what was once seen as an impregnable fortress can be viewed as a little less unbreachable after Los Blancos' smash and grab. Chelsea can now make the trip to Spain with greater belief that they can get the result in Barcelona's cauldron that they need.
The fear for the Blues though will be that Barca's two defeats will lead to a back-lash come Tuesday evening. Now with Guardiola effectively conceding the La Liga to Real Madrid, all focus will inevitably shift to Europe.
'We will see on Tuesday whether we will pass this test, but I think (the players) will lift themselves up and look at the manner of how things will go against Chelsea,' Guardiola told http://www.sport.es.
'What happens against Chelsea will mark the rest of our season. Although the guys have not had long to recover, they have had setbacks like this before and risen to the challenge.'
Certainly, a third straight defeat for Barca would be unthinkable and while not impossible, Chelsea must draw inspiration from Real's ability to penetrate Barca at home instead of looking to produce the same unlikely result. For a start, Chelsea do not have the squad or the tactical discipline to hit Barca on the counter so ruthlessly while at the same time keeping it water-tight at the back, which was Los Blancos' blueprint for success on Saturday.
Chelsea's 1-0 at Stamford Bridge may say otherwise, but observers of that game will have seen the Spaniard's miss a hatful of clear-cut chances to score that night. It is unlikely they will show the same profligacy in front of goal a second time.
Di Matteo must instruct his veterans to try and breach Barcelona instead of trying to hold them to a goalless draw. One goal for Chelsea will mean Barca will have to score twice to take the game to extra time.
And with the Catalans unable to rest any players as the Blues did on Saturday (Di Matteo rested eight of his first team) in a physically gruelling El Clasico encounter, extra-time would surely favour the Londoners.
The danger for them is the perception that the 1-0 in Stamford Bridge has created. Any idea that they can turn up looking for the same result on Tuesday will surely lead to their downfall. Chelsea must score, because Barcelona won't be so unlucky in front of goal a second time.