Northern Ireland come into the match with two impressive wins in Belfast, a 5-0 win over Bulgaria followed by a 2-0 win over Belarus.
Finishing top of the group will not only secure promotion, but will also keep open the possibility of a backdoor entry to the World Cup play-offs.
Charles said he thought it was a “very good performance” against Belarus, and winning builds confidence in a young Northern Ireland team, who had an average age of just 22.6 in their starting team on Friday.
“It’s also important to win games at a young age,” said midfielder Charles, who is only 21 years old.
“We have the confidence to face the next game and doing it away from home will be really good for us.”
Luxembourg are bottom of the group with two points from five games, although O’Neill warned that they are a better team than their results suggest.
This was echoed by Charles, who was impressed when they visited Windsor Park in September for a match that ended in a 2-0 Northern Ireland victory.
“They are much better than what they do. They like to play good football and develop from the back.
“They also have good individual players. We expect a difficult game and when they were in Belfast they caused us some problems.
“The main goal is to win the group and finish strong.”
