Never mind that Bayern Munich have now lost four in a row or that star men Arjen Robben and Franck Ribery are missing - this tie is far from over.
1) Bayern have been excellent at home (mostly)
Bayern may have lost their last two at home this season, but that has not been indicative of how well they've played at the Allianz Arena this year.
Bayern have won 19 and drawn one of their 23 matches in front of their home support (82.6 per cent) and have incredibly scored 70 goals in those matches, conceding just eight along the way.
They may be shorn of their two star attackers, but Bayern are still a force in front of their own.
Barcelona 3 Bayern Munich 0 player ratings
Barcelona 3 Bayern Munich 0 player ratings
1/24 Marc-Andre ter Stegen
Pressured by Bayern front line in attempt to hurry passing game. Escaped when Lewandowski missed cross but had fairly little to do. 6/10
2/24 Dani Alves
Played a key part in quarter-final win over PSG and went close to scoring but denied by Neuer. Booked for pulling back Lewandowski. 7
3/24 Gerard Pique
Censured for taking out Lewandowski shortly before hosts went ahead. Kept position but not troubled as much as may have feared beforehand. 6
4/24 Javier Mascherano
Stationed in makeshift back role he has become accustomed to. Rushed and harried by German visitors but calm in control and in his decision-making. 6
5/24 Jordi Alba
Played his part both at back and going forward, never stopping running all night. Beaten by Müller early on. Forced Boateng to rush a clearance. 7
6/24 Ivan Rakitic
Scored winner against Man City and was again the Croatian cog who kept the Catalans ticking over. Constantly probing and picking out team-mates. 8
7/24 Sergio Busquets
Laid the groundwork to allow his more celebrated colleagues to shine further upfield. Strong in the tackle and careful in possession all night. 6
8/24 Andres Iniesta
Delightful ball over Bayern back line was not converted by Alves. Danced through German midfield on occasion. Brought down by Benatia. 7
9/24 Lionel Messi
What else can be said? Smacked shot straight at Neuer but drove past German for first before impudent, glorious second. Set up the third for good measure. 9
10/24 Luis Suarez
Has been in superb form and started with menacing intent. Went down easily early on in optimistic penalty shout before being denied by Neuer. 7
Denied within sight of the goal-line by desperate block from countryman Rafinha. Halted by onrushing Neuer before curling over. Wasteful with shots. 7
12/24 Best off the bench: Xavi
Integral to Barça’s three Champions League triumphs of the last decade but reduced to bit part in what may be his final days at the Nou Camp. 6
13/24 Manuel Neuer
World’s number one No 1 did not look like being beaten before final 15 minutes, denying Suarez, Alves, Messi and Neymar. And then it all fell apart. 7/10
Formed part of experimental back line and struggled to keep check of home side’s runs. Made vital block as Neymar slid in but unable to prevent late goals. 6
15/24 Medhi Benatia
Caught playing offside as Suarez was allowed to race through alone and Guardiola’s risky formation was hastily altered. Booked for foul on Iniesta. 5
16/24 Jerome Boateng
Touched Suarez over in area but with nowhere near enough intent to cede spot-kick. Made to look foolish – one of many – by Messi for hosts’ second. 6
17/24 Philipp Lahm
Had hands full with defensive duties as the Spanish club made the early running. Brought down Messi to halt one attack before the interval. 7
18/24 Xabi Alonso
Former Liverpool man was first to enter the referee’s book. Linked up well with Lahm as he was booed by home crowd for his Real Madrid links. 6
19/24 Thiago Alcantara
Instrumental in last month’s thrashing of Porto and saw shot momentarily trouble Ter Stegen. Has work to do to match heights of Barça last night. 6
20/24 Bastian Schweinsteiger
Struggled to influence proceedings as he enters twilight of career. Fortunate to stay on pitch after coming-together with Suarez. 5
21/24 Juan Bernat
Diminutive Spaniard carelessly gave away possession to Messi to allow Argentine to open the scoring. Did not impress on return to his homeland. 5
22/24 Robert Lewandowski
Lacked vital touch as ball was fired in to him underneath the Barça crossbar by Müller. Kept close to Alves after break to limit damage from left flank. 6
23/24 Thomas Muller
Worked forward line well and also dropped out to the wings to retrieve lost causes. Beat Alba to feed Lewandowski but lost at sea as Barça prevailed. 6
24/24 Best off the bench: Mario Gotze
Entered fray after Barcelona went ahead in an attempt to provide more firepower but unable to achieve parity before Barcelona sealed victory.
2) They've been here before - in the last round
Cast your mind back to the quarter-final of this competition. After the first leg Bayern were staring an early exit in the face after a shock 3-1 defeat away to Porto.
What happened next? Bayern put in a performance for the ages to go 5-0 up before half-time.
Barcelona will, of course, provide a much tougher test than Porto did, and Bayern did have an away goal, but it's not too much of a stretch to believe Bayern could score three against this side - they had chances in the first leg.
3) The last time the two sides played at the Allianz
One does not have to go too far back into history to see Barcelona being dominated by Bayern in Germany. In 2013, Barcelona arrived and were promptly smashed 4-0 by Jupp Heynckes' team, who went on to win the treble that season.
A lot has changed since then but six or even seven Barcelona players who were part of that defeat will play on Tuesday night. Nightmares like that are hard to forget.
4) Pep Guardiola
Pep Guardiola took a battering after the defeat last week, with plenty questioning if the Spanish coach got all his success because he was lucky enough to inherit two of the very best teams in the world.
There is some truth in that but Guardiola is clearly a very talented manager who has too much pride not to force a big reaction from his team. He knows the Barcelona players better than almost anyone and while that didn't do much for him in the first leg, the Spaniard knows his reputation depends on a performance in this game.
5) Do Barcelona stick or twist?
It's something we've seen plenty of times (Porto, again) in the Champions League over the years, with players and coaches unsure whether to hold on to what they have or to go for the kill and potentially leave themselves exposed.
Barcelona have a commanding lead but if Bayern can get an early goal, the visitors won't be completely sure about how to approach the rest of the match.
Bayern have been poor recently but there is still plenty of football to play.Reuse content