It was only the Gunners' second away win since the New Year.
"I think we won just two away games in 2018," said Lacazette.
"We want to be better this season. It's good to have broken that barrier by winning our first game away.
"We can see that we have the right mentality. Last season, we would have lost that kind of game. If you look at our faces after the equaliser on the second goal, we had confidence and that's why we came back."