diff --git a/index.js b/index.js
index cf2af38e..2bab66a8 100644
--- a/index.js
+++ b/index.js
@@ -105,7 +105,7 @@ class ServerlessPythonRequirements {
   get targetFuncs() {
     let inputOpt = this.serverless.processedInput.options;
     return inputOpt.function
-      ? [inputOpt.functionObj]
+      ? [this.serverless.service.functions[inputOpt.function]]
       : values(this.serverless.service.functions).filter((func) => !func.image);
   }