diff --git a/lib/dalli/client.rb b/lib/dalli/client.rb
index <HASH>..<HASH> 100644
--- a/lib/dalli/client.rb
+++ b/lib/dalli/client.rb
@@ -269,7 +269,7 @@ module Dalli
     end
 
     def key_without_namespace(key)
-      @options[:namespace] ? key.gsub(%r(\A#{@options[:namespace]}:), '') : key
+      @options[:namespace] ? key.sub(%r(\A#{@options[:namespace]}:), '') : key
     end
 
     def normalize_options(opts)
Stop attempting to strip the namespace from a key multiple times