Galeno's stoppage time goal for Porto in the last-16 first-leg tie stunned Arsenal and interrupted a superb run of form since the turn of the year.
Arsenal will be confident of overturning that deficit in the second leg but before that, the priority for Arteta will be maintaining his side's Premier League title challenge.
The Gunners have won their last five league games, scoring 21 goals, and have the chance to close the gap on leaders Liverpool to two points with a victory over Newcastle in a Saturday night clash at The Emirates Stadium.
"What happened in another competition is there, but what you cannot deny is what is in your tummy after a defeat," Arteta told reporters.
"We have to use it in a really powerful way to be better."
Newcastle beat Arsenal 1-0 in November - a bitter defeat that left Arteta seething at the match officials.
While Newcastle's season has been impacted by injuries since then, Eddie Howe's side still pose a considerable threat.
"They are a really good team. They are very well coached, they have fantastic players," Arteta said.
"They have great spirit within the team and they are difficult to beat for us and for many, many opponents."
This time last season, Arsenal were involved in a two-horse title race with eventual champions Manchester City -- his side eventually crumbling under the pressure.
But this year, with a squad approaching full fitness and Liverpool also in the frame, Arteta said his team are right where they want to be.
"I feel a lot of excitement especially internally because we're right in the mix and we want to continue to be there," he said.
"Externally, probably it's different because the expectations are focused much more on the other two teams.
"I think we are in a really good position, we are what we want to be. I don't know if we can be better, I think the most important thing is that we continue to believe to perform at the level that we are doing and we have the squad available.
"And if we have those two things, we're going to give them a real go."
Arsenal could have a boost this weekend with midfielder Thomas Partey nearing a return from injury.
"We have another session today and obviously he's been out for many, many months now and we need to really nail the timing and when he has enough in the tank to compete, but I think he's very close," Arteta said.
