After being named in Victor Manuel Vucetich's first Mexico squad, the 24-year-old helped his club team to its fifth win in eight league matches this season.
With Villarreal already up a goal, Jonathan Pereira sent in a cross from the left flank that Dos Santos was able to beat the goalkeeper to, and with an extended boot, he doubled his team's advantage in the 49th minute.
The win pushed the Yellow Submarine to third in the La Liga standings, four points behind Atletico Madrid and Barcelona, and with one more game played in the young season.
For Dos Santos, it was his fourth league goal in eight matches with his new team, after completing a transfer from Mallorca in the offseason. He has also tallied three assists.