The Gunners were largely outplayed by their Championship opponents during the opening 45 minutes at Emirates Stadium, with Patrick Bamford hitting the bar with one of Leeds’ 15 shots at goal.
However, Arteta’s side were much brighter after the break and scored the game’s only goal 10 minutes into the second period through Reiss Nelson.
Lacazette, Nicolas Pepe and Gabriel Martinelli also went close to extending the lead as Arsenal ended the game strongly, with the win securing a fourth-round trip to Bournemouth.
Speaking after the game Lacazette revealed that Arteta was far from happy with his players at half-time and made his feelings clear in the dressing room.
“He shouted a lot! He was not happy because we knew they were going to play like this and we didn't respect what he said,” Lacazette told BBC Sport. “The second half was better and thank you, Reiss, for the goal!
“Emotions are very high. They played very well in the first half and of course Leeds are a great team, I think they pressed us and we didn't expect it. We got the final goal in the end and that's the most important thing.”
Goalscorer Nelson also praised Arteta’s rousing half-time teamtalk and hopes this win, combined with their New Year’s Day victory over Manchester United, can provide a platform to build on during the second half of the season.
“I think [shouting a lot] is good – as a coach you always need to have the aggressive side and obviously the side where he's loving as well,” the 20-year-old said.
“In training he's always asking us to press with passion and play with purpose. Sometimes we played out wide, sometimes we played down the middle and it's all paying off.
“It gives us confidence to go forward on the [Crystal] Palace game [on Saturday], we want to go there and we want to do well. Getting two wins at the Emirates is good and we're just going to carry on going forward.”