Aston Villa boss Unai Emery was in the stands to watch Real Union lose 3-2 against Osasuna B.
The Spaniard is the architect behind Villa's new agreement with Union to collaborate on technical and coaching methodology.
El Diario Vasco states that Emery attended the game with his brother Igor, who is the club's president.
Emery holds a stake in Real Union, who are in the Spanish third division, as his father and grandfather both played for the club.
There is still uncertainty about how such a partnership would benefit Aston Villa.