their first match was a great win which ensured them to enter the semi-finals. However, Dortmund may not be able to win in the next match, Barcelona will attack even more strongly in the next match and enter the semi-finals, besides, Barcelona has the possibility of entering the final.
Sure, you know the first leg is always more important than the second leg and now that barcelona have succeeded in wining them with 4 goals. The possibility for them to win back with this goal margin is something anyone can not think nor imagine that it will happen due to how consistant barcelona is towards chasing this champions league title, so I don't think if there's still a hope for dortmund.
Dortmund was an unlikely team before the match and now they will remain an impossible team after this score. Borussia Dortmund is a very high quality team but they still cannot be as good as Barcelona. Barcelona wants to win both the Champions League and La Liga this year and they have shown us that. Also, their players seem to be very ambitious this year. I think they will definitely achieve a victory as a result of this ambition. The match in Germany will not be a problem for them.