The Spanish midfielder recognised that the Gunners did not create the chances that reflected their possession of the ball in the 1-0 defeat to Norwich City on Saturday
The Spanish midfielder acknowledged that the amount of chances his side created did not reflect their control of the ball at Carrow Road.
Grant Holt's first-half goal was enough to separate the two teams as Arsenal fell 10 points behind Premier League leaders Chelsea.
"We're really down because we expected to win the game," Arteta told the club's official website. "They raised their game, they made it very difficult for us.
"I think we controlled the game, mostly, for 90 minutes. But you go a goal down, you start getting anxious, the goal doesn't come, it makes it really hard.
"For the amount of ball we had in the game, we should have done more and created more goal situations. We need more patience sometimes."
Arsenal have now conceded the first goal in their past four top-flight matches and Arteta insisted that the statistic must change.
The 30-year-old added that the team's disappointment was magnified because of the belief they have in themselves this season.
"It's not the first time we have conceded the first goal," Arteta continued. "It's very difficult.
"If you go ahead, it gives you a lift, the other team has to take risks, and you can cause mistakes. You can't get back in the game every time you fall behind. It's a tough ask and we haven't done it today.
"We have time to come back. But we are down because we know how good we are and how good we can be."