"Now it's more difficult, it's clear," Emery told reporters after Arsenal's third defeat in six league games following a 14-match unbeaten run earlier in the season.
"I think the most important thing for us is to recover our confidence and be more competitive. We need consistency over 38 matches. Now it isn't enough at the moment."
Arsenal have the opportunity to close the gap with Chelsea, who defeated Newcastle United last time out, when they host Maurizio Sarri's team on Saturday.
"The big opportunity for us is that we can take in our hands the possibility to be closer to them," Emery added.
"This (Saturday's) result makes that more difficult."
Emery will also keep an eye on a resurgent Manchester United who drew level with them on 41 points following their fifth Premier League win in a row under caretaker boss Ole Gunnar Solskjaer.
(Reporting by Rohith Nair in Bengaluru; Editing by Amlan Chakraborty)
