Arsenal snapped a three-game losing streak in the Premier League on Wednesday with a 1-1 draw at home to Southampton but sit five points above the relegation zone in 15th place.
"The coach is least to blame for the fact that we are in this situation," Leno told Sky Sports. "If you look at the way we were running around on the pitch at times, then the players are the only ones to blame.
"We're getting red cards, making mistakes, standing out of position. These are things that we have clearly addressed a thousand times. In the end, it's a lack of focus on the part of the players.
"The coach is not an issue in the dressing room, there is no criticism of him. We criticise ourselves and the players know that they are responsible."
Leno also said a lack of discipline had contributed to Arsenal's problems and the players were determined to put things right.
Arsenal have had seven players sent off since Arteta took charge last December -- twice more than any other club in the league.
"The attitude is bad, the discipline is lacking and we have no self-confidence," he added. "There are many factors at play here. We have addressed this very clearly internally and everyone agrees that we have to change this very quickly."
Arsenal's next match is a league trip to fifth-placed Everton on Saturday.