Champions League Second Legs Preview — Who Goes Through and Who Goes Out

The Champions League quarter-final second legs are here. Here is the specific mathematical situation for all four ties and who has the best chance of advancing.

The Champions League quarter-final second legs — all taking place on April 14-15 — will determine which four clubs advance to the semi-finals and which four are eliminated. The specific aggregate situations from the first legs create different mathematical challenges for each tie, and analysing each clearly reveals where the drama will be concentrated.

Real Madrid vs Bayern Munich (Real Madrid lead 3-1): Bayern need to score twice without conceding at the Allianz Arena to extend the tie to extra time. They need three without conceding to win in regular time. Against a Madrid side whose defensive organisation in second legs where they hold aggregate leads is historically formidable, this requires Bayern's best-night performance. Harry Kane will start, will be excellent, and will need at least two goals. The probability assessment: Real Madrid advance with approximately 75 percent probability.

PSG vs Liverpool (0-0 after first leg): perfectly even. One goal from either team changes the entire character of the second leg. Anfield's specific atmosphere — the crowd pressure that Liverpool's European nights generate — is the specific variable that the statistics cannot fully quantify. Salah at home, in what may be his last Champions League campaign with Liverpool, against PSG's defensive structure. This is the quarter-final second leg with the highest joint excitement ceiling. Probability: essentially 50/50.

Arsenal vs Sporting CP (Arsenal lead 2-0): Arsenal need to avoid a two-goal capitulation at the Emirates. Sporting need to score twice without conceding. Arsenal's home defensive record and the specific quality gap between the teams make this the most predictable second leg in the draw — Arsenal advance with approximately 85 percent probability. Sporting's comeback against Bodø/Glimt was extraordinary; Arsenal are not Bodø/Glimt.

Atlético Madrid vs Barcelona (Barcelona lead 2-1): Atlético need one goal to force extra time, two to win the tie outright. The Metropolitano at full capacity for a night with this specific emotional charge — Simeone's warriors needing to complete a comeback against their most historic rivals — creates the precise conditions that Atlético's specific game model was designed for. Probability: Barcelona advance with approximately 60 percent probability, but this is genuinely the most contested second leg in the draw.