Villa and Dortmund are underdogs so going through to the SF is going to be hard but not impossible. Porto were underdogs in 2004 but won the CL because Jose Mourinho had a talented team. They won the Primeira Liga, Taça de Portugal and UEFA Cup in 2003. Villa and Dortmund are not as talented as Porto were in 2004 but they have a slim chance against PSG and Barca.
Villa and Dortmund are underdogs, but still doubted them when they fight the strong club. They literally have overachieved this season. However it will be so good if neither of them can qualify for the quarter final.
They are having same bad performances at the domestic league, but did well at UCL.
As for their game, they undoubtly being unfavored in the quarter final. I consider they have to faced strong clubs such as PSG and Barcelona. I also doubt people would be betting on them as well.
Their quality are far compared to their opponent.