The Villans booked their place in the quarter-finals on Tuesday night thanks to a 3-2 win at Swindon Town.
"As people know, we've got a lot of young players. Everyone is still gelling together. It is still early doors," said Agbonlahor.
"But a cup run definitely helps. The victory will give us a fair bit of confidence for the matches we've got coming up.
"We haven't won for a few games and that will give us a lift and hopefully we can take that into the weekend."
Villa travel to Sunderland in the Premier League on Saturday.