I think Bayern could be pegged back tonight. Benfica were excellent in Munich and their atmosphere will be very hostile. If they get the first goal they could go through. Bayern have been wobbly under Pep in Europe.
Barca aren't through yet either. Atletico would have bitten your hand off if you'd have offered them 2-1 in Barcelona. A 1-0 win at home is their ideal result. Barca just don't sit back, it's not in their nature. They'll dominate possession and look to grind a resolute Atletico defence down. Atletico will counter and will create chances against Barca's defence with their full backs high up the pitch. It's the perfect scenario for Atleti to win so I wouldn't be surprised to see them in the semi.