The Brazilian completed a loan move to Villa earlier this week and started the game on the bench.
He watched on as Bruno Fernandes opened the scoring for the visitors after just six minutes.
The Portuguese’s speculative effort from 25 yards looked like it would be easily gathered by Emiliano Martinez.
But the Argentine produced a dreadful error as the ball squirmed between his legs and over the goalline.
Fernandes then doubled United’s advantage in the 67th minute as his effort found the net via the crossbar.
Moments later, Steven Gerrard turned to Coutinho to turn around his side’s fortunes.
And Coutinho played a massive role as Villa produced a comeback.
The 29-year-old played a key role in Jacob Ramsey’s equaliser in the 77th minute.
Five minutes later, Coutinho then equalised for his side as he turned in Ramsey’s cross from close range.
His goal sparked scenes of jubilation inside Villa Park.
There were no further goals as the two sides shared the spoils.
Aston Villa vs Manchester United Reaction | The Football Terrace
Coutinho spoke to the media after his dream debut.
He told Sky Sports: “I’ve missed these games. I’ve missed the Premier League. I am very happy to be here. It was a good start. I think we had a good game. We’ll keep believing to the end. We didn’t lose and we move on.”
Villa are next in action against Everton on January 22. After his cameo against United, it seems likely that Coutinho will make his first Villa start at Goodison Park.