The 18-year-old scored his first goal for the Red Devils in the club’s 4-0 victory over Wigan Athletic after completing a switch from Crewe Alexandra in July.
Powell, who scored in Crewe’s League Two play-off victory in May, is relishing the chance to play against Barcelona or Real Madrid in the latter stages of the competition.
“Growing up I always watched a lot of United in the competition and I can’t wait to be involved – it’s one of the biggest competitions around,” he told United’s website.
“Obviously everyone wants to win the Premier League, but being the best in Europe would be a great thing.
“The team want to improve after what happened last season and we’ll all be pushing hard to do well.
He added: “It’s a competition I’ve dreamt of playing in. When you watch the likes of United, Real Madrid and Barcelona, you want to play against them because they’re the best in the world.
“I’m just looking forward to experiencing the whole atmosphere of the games. You can get a lot of lively atmospheres in Europe – I’ve heard all about the Galatasaray fans and how much noise they make. Hopefully it will be a good game on Wednesday.”
• Galatasaray beat United on away goals in the 1993-94 second round after a 3-3 aggregate draw.
• The clubs met in the 1994-95 group stage, drawing 0-0 in Istanbul before a 4-0 United home victory on 7 December 1994, featuring David Beckham’s first goal for the club. United finished third in the section with Galatasaray fourth.
• Galatasaray have never won in England, where their record reads W0 D3 L4. Their most recent trip brought a 3-2 group stage defeat at Liverpool in 2006.
• United are beginning their 17th successive Champions League group-stage campaign.
MORE: The latest football news