Villa moved to third in the table and on course for a top-eight finish, 41 years after their last campaign at the highest level of European football.
"It's a bit surreal," McGinn told Amazon Prime after the game.
McGinn said he "didn't know" how far Villa could go in the Champions League this season, adding "obviously, it's our first season back in the Champions League for a long time, so we're just going to take each game as it comes.
"If we get into the top eight, brilliant. That's the target now and hopefully we can do that."
McGinn opened the scoring after just three minutes as Villa took the lead twice, only for Leipzig to equalise.
Veteran midfielder Ross Barkley came off the bench and scored the winner two minutes later, the long-range deflected effort being the 31-year-old's first Champions League goal.
"That's the role of the lads on the bench," Barkley told Amazon Prime. "I'm happy to come off the bench and score the winner."
"They all count, don't they?" Barkley said of his deflected winner.
Under the new Champions League format, the sides in the top eight qualify directly, while those from nine to 24 go through an extra knockout round.
Villa coach Unai Emery told reporters his side's performances in Europe had exceeded their pre-tournament expectations.
"Our target now is higher than when we started in this competition," the four-time Europa League winner said.
"Now we've achieved it with the top 24, maybe today with the top 16, and we have a chance at the top eight.
"Today was very important to take another step forward and be close to the top eight. We are recovering our confidence.
"We have to enjoy the journey together."
© 2024 AFP