"This evening we needed to see two or three good solutions with the new players," he told Sky Sports News.
"In the first half we suffered very much and Poland played very well. But our organisation and balance was very good and I think after the goal, in the second half, we played better and had more personality.
"The new players played very well and we are happy with the result. Poland did not deserve to lose but football is football."
"Sammon, physically and technically also, he played well but we know we have Shane Long. It was important to see McCarthy because he can grow," he added.
"I think our defenders are good enough - we have no other solutions in that position. We don't need to change many players."
Republic of Ireland's next match is the World Cup qualifier against Sweden next month.