The Gunners had to come from behind to edge seventh-placed Wolverhampton, who went ahead in the 10th minute from Hwang Hee-Chan who swooped on a defensive error.
Substitute Nicolas Pepe levelled the game in the 82nd minute, before Lacazette’s late effort went in, moving Arsenal above West Ham United into fifth.
The Gunners are one point behind fourth-placed Manchester United who have played two games more as well.
“It pulled us a little bit closer. One game less and three points. 13 games to go, and now its about Watford,” Arsenal boss Mikel Arteta told reporters.
“I think it’s about belief, that we should keep playing the way that we are playing - and keep insisting - and have that resilience and that capacity to dominate matches like we are doing right now… and then that’s the energy and (synergy) with our fans to create a special atmosphere. Where people don’t want to come and play against Arsenal.”
The win was significant with Wolves in European contention and proving difficult to break down this season, having conceded only 18 league goals in 24 games prior to Thursday.
Wolves also took an early lead, thus Arsenal’s fightback was impressive, although Arteta wouldn’t be drawn into discussing how momentous it could be.
“We don’t know because we are not there yet. When we are there I will tell you how important it is,” the Spaniard said.
“Today what is important is that we focus on playing better, maintain that capacity as a team to dominate and take the game where we want, and that’s what I want from everybody involved, especially the subs because today I think they were magnificent.
“There are some good examples for them to use tomorrow and we will keep going.”