diff --git a/pino.js b/pino.js
index 2398e5acb..55032a06b 100644
--- a/pino.js
+++ b/pino.js
@@ -89,7 +89,12 @@ function pino (...args) {
   const instance = {}
   const { opts, stream } = normalize(instance, caller(), ...args)
 
-  if (opts.level && typeof opts.level === 'string' && DEFAULT_LEVELS[opts.level.toLowerCase()] !== undefined) opts.level = opts.level.toLowerCase()
+  if (
+    opts.level &&
+    typeof opts.level === 'string' &&
+    DEFAULT_LEVELS[opts.level.toLowerCase()] !== undefined &&
+    !opts.useOnlyCustomLevels
+  ) { opts.level = opts.level.toLowerCase() }
 
   const {
     redact,