Arsene Wenger admitted his decision not to start Alexis Sanchez was "debatable" after his side fell to a 3-1 defeat at Liverpool on Saturday.
Liverpool were already ahead 2-0 when Wenger brought on Sanchez at half-time, and the deficit proved to much to overcome as Arsenal fell out of the top-four to increase the pressure on their manager.
Asked if not starting Sanchez backfired, Wenger told BT Sport: "I felt the strikers suffered in the first half and we didn't dominate in the midfield. It is always debatable."
Roberto Firmino and Sadio Mane starred for Liverpool in the first half, assisting on each other's goals while Arsenal looked out of sorts, and Wenger said: "We had problems getting into the rhythm of the first half."
"We conceded cheap goals -- direct balls from the goalkeeper and you do not expect that in a game like this but we came back in the second half, responded well, but didn't perform at our level in the first half."
But Wenger remained positive that Arsenal were still in a position to challenge for the top four.
Asked if the result knocked them out of the top-four race, he responded: "It is a possibility to be in it as well so let's focus on that."
Liverpool midfielder Adam Lallana admitted Arsenal put the hosts under pressure after Danny Welbeck got a goal back in the 57th minute.
"We went in at half time 2-0 up and were pleased with our performance," Lallana said. "But it shows that in this game you can't take anything for granted. We had to dig in at 2-1.
"We are still young and still feel we are learning. Of course we are disappointed with how inconsistent we have been since Christmas but it is up to us to put that right."
Sadio Mane was happy with Liverpool's response following Monday's disappointing defeat at Leicester.
"The most important thing is the reaction to losing and we reacted today and got the three points. The performance of the team was great.
"We work together as a team, we were compact from the beginning until the end and we are happy to win."