The win booked the Red Devils’ spot in the final 16 of the competition, but they had to come from behind in Portugal to claim the three points.
Van Persie netted the equaliser for United and Giggs celebrated the Dutchman’s recent form after the game:
“Robin gets one chance and he puts it away,” He told SkySports.
“He’s just scoring goals for fun at the moment.
“With the form he’s in, his confidence is high and I think everyone knew he was going to score.”
The Premier League side failed to advance from what was a fairly weak group in last year’s tournament, dropping into the Europa League.
The Welshman believes those memories can be put to bed now as the club prepare for the knockout phase of the competition:
“We were all disappointed” Giggs told Sky Sports.
“It wasn’t good enough. We knew we had to do something about it and we have.
“We hope this continues now. We’re in good form, both in the league and the Champions League, so we have to carry it on now.”
Alan put Braga ahead just after half time, converting from the penalty spot following Jonny Evans’ foul on Custodio.
United began their comeback in the 80th minute through Van Persie. Wayne Rooney then added a second via a penalty-kick before Javier Hernandez completed the scoring in injury time.