Muamba, recalled in place of Mancienne on Sunday night, defended the overall record of Pearce, who has been assured the two-year contract extension he was poised to sign before leaving for Denmark is still on the table.
"You don't judge the gaffer on just one tournament," said Bolton star Muamba.
"He took us to two semi-finals and one final. I'm sure the team that comes in, in 2013 will do better."
Muamba added of the tournament: "We never really dealt with it properly.
"You'd expect us to win at least one of the first two games and give ourselves a better chance.
"There are always excuses on top of excuses. We just have to look at ourselves in the mirror, look at what went wrong and rectify it in the future."