It was a welcome boost for Nigel Adkins' side, and Horsfield - on loan from Sheffield United - was relieved to get off to a good start in claret and blue.
"I've only been with the lads since Thursday but they seem like a good bunch. It's good for them that we've been able to come out of a bad run and get a great result against a team like Charlton that are trying to get in the Premier League.
"I was happy with my performance and how it went. My fitness was okay, to say I haven't played much, but I thought I should have scored early on when I put a header wide.
"We had to work harder still when Andy Butler got sent off, but it's a big win for everyone and we deserved it. I enjoyed the battle."