The German striker settled Sunday's meeting at Anfield in the 16th minute, finishing Declan Rice's low delivery after Arsenal had won possession from a Liverpool goal-kick.
The result gave Arsenal their first Premier League victory at Anfield in 14 years and moved them three points clear at the top of the table. It was a particularly satisfying response after their League Cup elimination against Fleetwood Town.
Arteta was delighted with the reaction from his players following that disappointment.
“Now, it feels better as a manager because it's been such a long time without having this feeling here that we really needed it. We're extremely proud of what the team, the players, everybody has done,” he said.
“Especially in the condition that we arrived to this game, where we were after the defeat against Fleetwood, it looks like the end of the world. It looks like, yeah, what are we doing? Then you have to pick yourself up, understand that this is the beautiful part of this game.”
The Arsenal manager felt his side had earned the victory through their preparation and commitment, despite acknowledging the threat posed by Liverpool.
“We knew that we needed to nail absolutely all of them and we were going to have to navigate through periods that we were going to have to suffer because they are extremely good at doing that and creating those vertical attacks, those chaos moments for almost nothing,” he explained.
“You really need to enjoy that. If you don't, there will be a moment that you will switch off and they will punish you. I think the way we competed and played and the chances that we generated as well, it was really impressive so I'm really happy.”
Arteta was particularly impressed by Arsenal's defensive work, with Liverpool unable to register a shot on target despite having several opportunities.
“I didn't know about that statistic but that's incredible. It didn't feel like this to be fair on the pitch because there were very little margins sometimes when they had the opportunity to shoot and it's a team that shoots a lot,” he said.
“You have to be so good at blocking shots and preventing those spaces for them to get into there. Again, it's a commitment of every single player in every action consistently to deliver those kind of stats and to do it against this team, it's something remarkable I would say.”
Liverpool responded strongly after conceding and came close to equalising before half-time. Florian Wirtz struck the crossbar with a free-kick, while Alexis Mac Allister headed over from a promising position.
Iraola believed his team had done enough to take something from the match, but admitted their opening period had fallen below the required standard.
“Overall, I think we have to blame especially the start of the game and until we conceded the goal. I think the start hasn't been at the level of the game,” the Liverpool head coach said.
“But from that 1-0, I think it's [after] 15 or 16 minutes, I've loved the reaction of the team. Even in the first half, I think we reacted really well and put Arsenal under big pressure.”
The Spaniard pointed to the chances Liverpool created and felt the hosts should have been awarded a penalty when Alexander Isak's shirt was pulled in the area.
“I think we've done enough to score but obviously we haven't. But we had the crossbar, we had the header of Mac Allister that, for me, is a very clear chance. I think we had a clear penalty also for us.”
Iraola was particularly frustrated that the officials did not award a spot-kick for the incident involving Isak.
“He is going to head the ball in front of the goal and they grab him where everyone sees the shirt. You don't need a lot just to avoid Alex because the ball just goes in front of him and I don't see the reason why [it is not given],” he said.
“Probably because he doesn't dive or he doesn't go to the floor – it shouldn't be a reason not to concede a penalty.”
Despite the disappointment, Iraola was encouraged by Liverpool's response after going behind and the pressure they applied during the remainder of the contest.
“I think from when we conceded the goal until half-time, we had very good moments, a very good 30 minutes. It looked quite close, a goal. We've put them under pressure, we've put them inside the box, we've put them there, but we haven't had the clarity to finish the situations better.”
Arsenal, meanwhile, defended their advantage after the interval, with goalkeeper David Raya and the visitors' back line helping to preserve the clean sheet.
Arteta was also keen to acknowledge the quality of the opposition, praising Liverpool's approach and the difficulty of securing a result at Anfield.