Consecutive Premier League defeats, by Manchester City and Chelsea, have left the north Londoners significantly off the pace in the race for a top-four finish.
The Gunners are currently in sixth place in the Premier League table, seven points behind arch-rivals Tottenham, who occupy fourth spot.
Arsenal can close the gap to four points if they win their game in hand against West Ham at Emirates Stadium on Wednesday night.
But Wenger is under no illusions about the size of the task that awaits his squad if they are to reach Europe’s elite club competition next term.
“It is frustrating as we don’t want to be in this position,” said Wenger.
“We want to challenge for the championship and therefore now until the end of the season we really have to stand up and show our strength and character.
“Last season we came from further behind and finished third but Chelsea are a bit away from us now. The game that we lost at Chelsea on Sunday had difficult mathematical consequences.”
MORE: The latest football news