By David Brenchley
After a fairly even first half, the Gunners came out in the second period firing on all cylinders and, in the end, proved too hot for their London rivals to handle.
Rachel Yankey opened the scoring just after the hour mark before substitute Carter fired in two 25-yard wonderstrikes to seal a flattering 3-0 victory.
"At this stage of the season the win is the most important thing," the Arsenal manager said. "Three goals flattered us a little, but the goals we scored were fantastic finishes.
"Dan has had a tough year. She is a young kid, really ambitious and stepping up into this team is always difficult.
"She hasn't scored for a long time but the goals she scored were fantastic and I am really pleased for her because she has had a tough year and she really deserves that."
The Gunners are currently sitting in second place after what Harvey would describe as a disappointing first half to the season but now seem to be getting back to their best.
"We know we haven't performed well in a lot of games but in the last 20 minutes tonight we were awesome again and we just have to put that into the first half of games and we will be alright.
"I have said for a long time I feel we have the strongest squad in the league; to be able to bring Dan Carter off the bench and have Jayne Ludlow and Faye White on the bench [is testament to that].
"We have a strong squad and we have to make sure we keep everyone fit and push on for the next four or five games and keep the league in our hands."
Goalscorer Carter was similarly delighted with her impact and has now set her sights on pushing to start games between now and the end of the season, and to help the Gunners overhaul Birmingham at the top of the table.
"Hopefully I can continue this form now and take it into the upcoming games. I just have to see how it goes in training now and take it from there," she said.
"We are all determined. We still have the belief that we can win the league. It's not over yet and we just have to win our remaining games now."
Meanwhile, Harvey's opposite number Matt Beard was devastated by the result and is disappointed his side have now slipped out of the top three, and also the hunt to become the inaugural FA WSL champions.
He said: "We had good chances tonight to go one maybe two-nil up and we haven't taken those chances. That has been the story of our season and it has come back and cost us dearly tonight.
"I said to the players this has probably been the worst week of my football life.
"We were sitting third in the table, still in the hunt to be there or thereabouts, and we have lost to Everton, who have now gone ahead of us on points, and Arsenal and Birmingham are now completely out of our reach."
