Sanchez fired wide of the target from a free kick on the half-hour mark and almost teed up Luke Shaw for a goal, but he ultimately could not help his side find a way through before being replaced after 65 minutes.
Regardless of Sanchez's lack of impact at the Levi's Stadium, Mourinho was pleased to have his January signing available for selection.
"It was good for Alexis," he told MUTV. "He needed this and he made a good effort, a good physical effort, which is important for him in this moment."
Sanchez scored two goals in 12 Premier League matches for United in the second half of last season.