McCarthy admitted after the final whistle that his side now faced an uphill task to qualify for the quarter-final stage in their maiden campaign.
"In recent weeks we've created so many chances without scoring," McCarthy said post-match.
"Today we couldn't break them down, and when you allow the opposition to get in behind and score then it'll be a long day.
"Tough luck, and we'll take it on the chin but now we've left ourselves with a mountain to climb in relying on other results.
"It's not how we wanted it to be, but that's it."