The Seagulls started the tournament with a seven-goal thriller against Chelsea, losing 4-3 in one of three matches that were played in Philadelphia.
“It’s great for the club to be competing in a competition like this,” midfielder Lallana told the club’s official website. “With the style of football we’re playing I think we’re different and it’s nice for fans in the USA to come and check us out.
“It was a very entertaining game for the fans I am sure, we played some really good stuff.
“I’ve loved coming out to America. It’s amazing and we love it out here. Everything is so big, it’s incredible. It’s a shame we’re not able to be here for a bit longer.”
Lallana says it works both ways and he was similarly thrilled to get to appear at Lincoln Financial Field.
“I loved playing there,” he added. “We’ve got a big group of NFL fans in the team, so just to come and play at the Eagles’ stadium was an incredible experience. It was a nice one to tick off the list and a great atmosphere to play in.
“A couple of the lads managed to get out and have a cheese steak. I was hoping we’d have some after the game but there weren’t any, and we checked out early so I didn’t get the chance to have one!
“I couldn’t have one for breakfast, it would have been a bit heavy probably. We tried to see as much as we could in our short stay.”
Brighton are next in action in the Summer Series on Wednesday, facing Brentford at Mercedes-Benz Stadium in Atlanta.