Arsenal defender Laurent Koscielny believes his team-mates had started to think victories were coming too easily prior to their recent slump in form.
The Gunners, who host Crystal Palace on Sunday, had gone 14 Premier League matches unbeaten - winning 10 - after their opening-day defeat to Liverpool.
However, Arsenal lost consecutive matches to Everton and Manchester City in December despite taking the lead in each of the games and Koscielny thinks the players were switching off due to their impressive run of form.
Koscielny told Sky Sports: "When you have so many good results in a row after the Liverpool defeat, we were in too comfortable a position, and think we can win easily every time - it is not like this in football.
"You can have all the talent, but if you don't put everything in, help your team-mates, you can have bad results. We lost this teamwork quality in the two games we lost.
"Because we scored first in both games we stopped playing. We waited for our opponent to do something.
"We were in too comfortable a position. We needed to push ourselves to score that second goal. That could make a real difference for us."
However, Koscielny was impressed by the way Arsenal recovered to earn a 1-0 victory over West Brom on Boxing Day, a result that has them in fourth place ahead of the match with Palace.
He added: "It was a hard game, as West Brom played very well.
"They tried to play on the counter-attack, which made it difficult. We were more incisive, and physically we were better than the two games before.
"We tried everything on the pitch to find a solution. It is difficult to play against teams who sit back very deep. We got the late goal, and got the three points. That is what is most important.
"We showed our character against West Brom and it is important to keep this mentality for the rest of the season."
