The Gunners’ Champions League qualification hopes took a hit in losing a game they expected to win, with Palace claiming their eighth victory on the road this term.
Granit Xhaka should recover from a hip complaint in time for Wednesday’s league trip to Wolves, as manager Emery looks set to mix up selection once again.
‘We have had some injuries, like with Aaron Ramsey, and we need to protect the players,’ said Emery.
‘For example, Xhaka asked to change in the second half against Napoli and could have played (against Palace), but with some risk.
‘We need to protect our players and to use other players.
‘We are playing with a lot of players and they give us the performance; we lost but we could also have lost with other players on the pitch.’
Christian Benteke, Wilfried Zaha and James McArthur all found the net as Palace thwarted the Gunners, who had Mesut Ozil and Pierre-Emerick Aubameyang on target.
Shkodran Mustafi endured a day to forget, the German producing errors to contribute to all three Palace goals.
Emery maintained switching formation at half-time to chase victory had opened more spaces in behind, in his defence of Mustafi.
‘In the first half we continued with the three central defenders because I think we can be more consistent with that,’ said Emery.
‘In the second half we changed to play with two and we can take more possibilities in the attacking third, in the build-up, but defensively we gave them more space to take the transitions.’