Arteta believes there is no need to panic and rush to judge the new forwards too hastily.
Asked about Giroud, the 30-year-old midfielder told the Mirror: "Look, it's two games. In fact, he has started just one game. [Comparisons are] not fair on him.
"He has played 90 minutes here. He played 25 minutes in the last one. A striker has to be relaxed. He doesn't need to be tense.
"Of course, you can't replace Robin. We know that - it doesn't matter who is brought in.
"Manchester United went for him at the age of 29. What does that say? There aren't many bigger talents in the world.
"To replace Robin is an impossible thing because he's a special player. You can't ask anyone to be as good as him. I don't think it's possible.
"Last week, Olivier had a massive chance to win the game and he would have been the hero.
"And Lukas had a chance here. Personally, I'm happy because they look good.
"We need to find the right balance. You might be more creative, but you may become more open and concede more goals to get the right results.
"We have done enough to win both games, we have created enough. For me we have lost two points."