Bayern Munich have pulled off a remarkable comeback to book their spot in the semi-finals of the 2014/15 UEFA Champions League.

The German giants trailed FC Porto 3-1 going into the quarter-final second leg at the Allianz Arena but not even Pep Guardiola could have dreamed up a batter outcome for his side on what was a memorable night for Bayern.

The Bundesliga champions won 6-1 to move through to the final four 7-4 on aggregate thanks to a blistering first half.

Goals from Thiago Alcantara, Jerome Boateng, Robert Lewandowski (two) and Thomas Muller had Bayern 5-0 ahead at the break before Jackson Martinez pulled one back for Porto in the 73rd minute.

But Xabi Alonso produced the icing on the cake with two minutes remaining to send Guardiola's men into the next stage after it appeared seemingly impossible following the disastrous first leg in Portugal last week.

Joining Bayern in the semi-finals is Catalan giants Barcelona who cruised past French champions Paris Saint-Germain 2-0 at Camp Nou to score a 5-1 aggregate triumph.

Brazilian ace Neymar, who scored in Paris last week, netted a first-half brace to allow Luis Enrique's men to move through to a the penultimate stage of Europe's premier club competition where they will strive to qualify for their first final since 2011.

Wednesday night sees Real Madrid host Atletico Madrid following last week's 0-0 draw as Juventus head to Monaco with a narrow 1-0 advantage.

2014/15 UEFA Champions League - quarter-final 2nd leg

Barcelona (SPN): 2 (Neymar 14'/34') Paris Saint-Germain (FRA): 0 Camp Nou, Barcelona, Spain - 84,477

*Barcelona wins 5-1 on aggregate*

Bayern Munich (GER): 6 (Thiago Alcantara 14', Jerome Boateng 22', Robert Lewandowski 27'/40', Thomas Muller 36', Xabi Alonso 88') FC Porto (POR): 1 (Jackson Martinez 73', red card: Marcano 87') Allianz Arena, Munich, Germany - 70,000

*Bayern wins 7-4 on aggregate*