The Spain striker replaced Pedro in the 75th minute of the match against Real Sociedad last night for his first competitive appearance since breaking his leg at the end of last year.
It took less than ten minutes for Villa to find his scoring touch as he scored the fifth in a 5-1 rout at the Nou Camp.
"You're fortunate when so many people help you, it's difficult to thank them all," he told Sport newspaper.
"I want to extend my gratitude to everyone, without them I would not have managed it."
"I'm happy with how the day went, I've taken a very important step forward, it was an intensive 20 minutes. Now I need to continue training," he said.
"I've spent a lot of time working and I still need to continue working, and enjoying it like I did today. Let's hope it continues like that."
The 24-year-old Cameroon international was undertaking his medical with the Primera Division outfit this morning and, if all goes to plan, he will put pen to paper on a five-year contract with Barca.
New Barca coach Tito Vilanova, who made his competitive debut in the Nou Camp hotseat last night after replacing Pep Guardiola this summer, said of Song: "He's a player that gives us a bit of height. He'll surprise us with his skill, he's a great player."