The Belgium international’s display in Sunday’s 1-0 win over Manchester City was among his best since joining from Everton in a £50million club record deal 15 months ago.
Emery has demanded more consistency from Onana this season after a debut campaign in which he started only 20 Premier League matches.
And while he believes the 24-year-old has been “fantastic” since returning from a hamstring injury earlier this month, he wants him to now keep hitting those levels.