Valencia did not perform badly in this match. The team has only 24% ball possession. However, we saw some excellent and powerful attacks from Valencia's players. Despite having 76% of the ball possession, Girona's players made a total of 9 shots, while Valencia's players also managed 9 shots. I would say Girona were very lucky in this match, so they managed to get full 3 points. Girona equalized in the 82nd minute with Stuani's goal. And just 6 minutes later Stuani scored another goal to give Girona the win.
You are generally right about the number of shots being equal for the two teams, but that is not the most compelling statistic in this game. Valencia didn't only have 24% ball possession, which by the way is extremely low, but they also had a passing accuracy of below 70% (68% to be exact). They didn't get into the game ever. Of course they are no amateurs and will have their small chances with counter attacks, but I doubt that anyone would try to convince me how well Valencia played when about every third pass of theirs missed the target, which means did not reach a teammate. That was not a good game for Valencia.