The much-changed side, including newcomers Scott McTominay, Scott McKenna, Kevin McDonald, Oliver McBurnie and Jamie Murphy, put in a laboured performance in the first half as the Central American visitors won 1-0 at Hampden Park.
McLeish, however, was not too disappointed with the defeat.
"It's a building process. They're a well-drilled team and we're a work in progress and still to get the team to play with a rhythm," McLeish told Sky Sports.
"It can happen that when you look at a team on paper and think it's a great team, many times in my career I've rotated a team and thought it's a good team but they've struggled a little bit, and we had that in the first half.
"It's not a competition, that's why we're experimenting, I'd love to have a great win ratio but sometimes you have to make some sacrifice and we've learnt a lot tonight."
McLeish had a previous successful spell as Scotland manager in 2007.
Scotland, who failed to qualify for this year's World Cup finals, play their next friendly against Hungary on Tuesday.
(Reporting by Aditi Prakash in Bengaluru; Editing by Toby Davis)
Share
