The Gunners registered their first away win of the season, and only their second of the entire calendar year, after Alexandre Lacazettes goal nine minutes from full-time helped them edge past Neil Warnocks newly promoted side.
Cech continues to keep summer signing Bernd Leno out of the team but again struggled with his distribution, most notably when he provided Harry Arter with a golden opportunity to open the scoring early on when he passed the ball straight to the Cardiff midfielder.
The former Chelsea stalwart also went walkabouts late on, an error which almost allowed Sean Morrison to score an injury-time equaliser, but Emery insists Cech remains a valuable member of his squad.
He has experience. He is intelligent. He is doing what we want, said Emery. Its very important for me to continue doing this and to keep improving.
We take a little risk, but when you break this risk and their pressing you can find space. We need to continue with this personality.
Emery also praised the contribution of Mesut Ozil who returned to the starting line-up after missing last weekends win over West Ham.
He said: Ozil with his quality I think we need him to give us his moments in the match.
I think today in the second half he played a good match, he worked every minute he was on the pitch. Maybe in the second half with his position on the pitch I think he feels better.
More: Arsenal FC