Arsenal manager Arsene Wenger has told his players to "wake up and be focused" when they host champions Manchester United next weekend after back-to-back Premier League defeats.
After a poor start to the season, the north London side had turned around their form to rise from the lower part of the table into the top four but Sunday's 3-2 defeat against promoted Swansea City and a 2-1 loss at Fulham have stalled the progress.
Arsenal are in fifth place, 12 points behind the two Manchester clubs who are level on points.
"That's now twice -- at Swansea and at Fulham - where we have given the game away," Wenger was quoted as saying by the club's website.
"At our level that is frustrating and not good enough. It is down to a lack of composure and the right decision-making. "It is alarming because at Fulham we were 1-0 up and we lost the game. (Against Swansea) we came back to 2-2 and straight away we gave the third goal away. It is really a concern."
Arsenal have lost seven league matches this season and are determined not to add to the tally when United visit the Emirates next Sunday.
"It is a massive opportunity (next Sunday) because you feel we have given six points away in the last two games in a way that is unbelievable," Wenger said.
"It is time for us to wake up and be focused -- we have a good opportunity to do that against Manchester United."
Arsenal, whose below-par season has coincided with arch rivals Tottenham Hotspur challenging the Manchester clubs for the title, have been boosted by the short-term loan signing of their all-time leading goalscorer Thierry Henry.
The Frenchman, who plays for Major League Soccer outfit New York Red Bulls, enjoyed a dream return when he came off the bench to score the winner in their FA Cup third round win over Leeds United last week but even that has soured a little.
Monday's British newspapers reported Henry had been involved in a heated verbal exchange with an Arsenal supporter after the Swansea defeat when he gestured at the fan and urged him to be more positive and get behind his team.