Santillan (1-0) picked up the win in Thursday's game against Washington. He allowed one hit in a scoreless ninth inning in a 5-4 extra-inning victory.
Santillan was activated off the 60-day injured list earlier in the day and made his season debut. He was one of six Reds relievers to work Thursday. Santillan is expected to be a key bridge to Alexis Diaz and the high-leverage crew.