Marcel Granollers is actually in the 23th position in ATP ranking while Paul-Henri Mathieu stands in the 261th position.
These two players have played twice against each other and Marcel Granollers had done very well to beat Paul-Henri Mathieu in both those encounters.
Paul-Henri Mathieu did very well to beat in the previous round John Isner in five sets and in a very tough match with 34 games in the final set while Marcel Granollers did very well to beat Malek Jaziri in a very tough match also in five sets.
In my opinion Paul-Henri Mathieu must be very tired from a long match (over five hours) that he did had against John Isner..
I think Mathieu is to much hyped after his match against Isner!
I will in 7 out of 10 times, pick Granollers here.. Which is 70/30 = great value!