Howat and Larkin scored in the second-half to put Palace into what seemed like a comfortable lead, before Emma Bissell's 80 minute penalty reduced the deficit to just one.
Potter spoke about the feeling in the dugout throughout those nervy final moments.
She said: "We just felt like we were getting sucker-punch after sucker-punch just as we were getting into a good rhythm.
"As I say, Charlton do that extremely well. I thought the girls managed it really, really well because they could have got really frustrated.
"I was getting frustrated on the side and they didn't - they managed it extremely well.
"That last five minutes or so, they managed the game really well.
"They put the ball into certain areas where we needed the ball, bought fouls, bought free-kicks, bought throw-ins in certain areas, and it just killed the game for us.
"It was a nervy last ten minutes - I was feeling it, but the players were outstanding."