Arsenal defender Laurent Koscielny has suggested that manager Arsene Wenger picked the wrong starting XI to face Chelsea last weekend.
The Gunners were on the end of a 3-1 loss at Stamford Bridge on Saturday.
The result pushed them further behind in the title race, with the Blues holding a nine-point lead over the rest of the pack, while Arsenal are 12 points adrift from top spot in fourth.
Koscielny has blamed team selection and the players' performances for the defeat to their West London rivals.
"I think we played some players in front of others and I think we should have played more as a team and there was space to do so. They hit us on the counter," The Mirror quotes Koscielny as saying.
"It will be difficult [to win the title] now. Mathematically, nothing is done but we know that it is going to be very complicated. We need to come back to the quality of our game, our passing, movement."
Arsenal defeated Chelsea 3-0 at the Emirates in September, but it proved to be a turning point for the Blues as they went on to win 13 league games in a row.