Lionel Messi
Lionel Messi scores his brilliant second goal for Barcelona against Bayern Munich. Reuters

With so much on the line, a second match still to come and the perilous threat of away goals, the first legs of Champions League semifinals can often be cagey affairs. Certainly that was the case last season, notably in the instantly forgettable goalless draw between Atletico Madrid and Chelsea. But this year it was different. This time there were fireworks aplenty. Juventus were rewarded for their cautious positivity when upsetting holders Real Madrid with a 2-1 victory in Turin. A day later came a classic encounter at the Camp Nou, decided by the brilliance of Lionel Messi to lead Barcelona to a 3-0 lead over Bayern Munich.

Here’s how the two matchups look going into next week’s second legs.

Bayern Munich vs. Real Madrid (Tuesday, 2:45 p.m. EDT)
For 76 minutes, Bayern Munich survived a remarkably bold early tactical plan, Barcelona’s exceptional attack and the absence of two-and-a-half of their own three-man frontline to stand goalless at the Camp Nou. But by the time the final whistle had been blown less than 20 minutes later, Messi had showed why he may well be the greatest player of all time and it was hard not to conclude that the semifinal had been decided.

An error under pressure from the Bayern defense and then the magical grace of Messi’s movement and caressing touch of the ball saw the Argentinean score twice in four minutes. At 2-0 the task for Bayern heading back to the Allianz Arena was incredibly difficult. Knowing that the away-goals rule meant that making it 2-1 would be far more significant than falling 3-0 behind, Pep Guardiola rolled the dice. But as Bayern pushed for that vital away goal, they left the backdoor wide open for Messi to find Neymar to roll a shot past Manuel Neuer. Such deficits have been overcome before in this competition, indeed Barcelona came from 3-0 down to beat Swedish side Gothenburg in the 1985-1986 semifinals. But it would take a major leap of faith to think that Bayern can pull off something similar.

When the second leg rolls around next Tuesday there will still be no Arjen Robben, no Franck Ribery. And even though Robert Lewandowski should be sharper after his facial injuries, the problem for Bayern will be the same: lacking the pace to strike on the break, how can they pose an attacking threat without leaving themselves vulnerable at the back? Scoring three goals is difficult enough, shutting down the most potent attacking trio in the world is quite another. One goal for Barcelona would leave Bayern needing five.

Prediction: Barcelona to make the final.

Juventus vs. Real Madrid (Wednesday, 2:45 p.m. EDT)
Massimiliano Allegri continued to enhance his reputation this season by getting his approach just right to strike the first blow against the defending champions. Defending deep to limit the effectiveness of Real Madrid’s devastating pace, Juventus retained a real threat themselves through their impressive forward duo of Carlos Tevez and Alvaro Morata.

After Ronaldo had been left free in the middle to cancel out Morata’s opener, Tevez broke clear to win and then convert a penalty. And it was only late on, after Madrid went to three up front, that Juventus lived up to the outdated Italian "catenaccio" stereotype, moving to five at the back and holding what they had. The key question for the Italian champions heading to the Spanish capital is whether Allegri will now start with three center-backs as he did when successfully holding onto their slender first-leg advantage in the quarterfinals against Monaco. Juventus have the plenty of resilience and knowhow but inviting pressure for 90 minutes against Madrid would be a risky strategy.

Perhaps the bigger questions, though, surround Real Madrid and Carlo Ancelotti. His two big selection decisions in Turin backfired, with Sergio Ramos showing his limitations in midfield and Gareth Bale lacking sharpness and confidence in his first start since injury up front. While Juventus should have Paul Pogba back available, Luka Modric will not be back by the time of the second leg to hand Ancelotti an easy solution in midfield. Balancing a team in which he is compelled to play his stars, without the aid of Modric, is a huge challenge for Ancelotti and one that could determine whether he is still in a job at the Bernabeu next season.

Prediction: Juventus to make the final.