"I am pleased with how it went," said Darby after Tuesday's friendly against Hertha Berlin.
"To play in that stadium was great. I think the attendance was 51,000, which is the biggest crowd I've played in front of. I'd obviously like to do it more often in the future.
"It has been an amazing experience to play alongside the first team through pre-season. It's the kind of thing you dream about as a kid. Hopefully there is more of it to come during the season.
"The main differences I have noticed are the speed of the game and the strength of the players, but Rafa, Sammy Lee and the other staff have been and always are here to help me improve."