diff --git a/lib/sidekiq/middleware/chain.rb b/lib/sidekiq/middleware/chain.rb
index e60d5b15..335fa281 100644
--- a/lib/sidekiq/middleware/chain.rb
+++ b/lib/sidekiq/middleware/chain.rb
@@ -77,13 +77,13 @@ module Sidekiq
       end
 
       def insert_before(oldklass, newklass, *args)
-        new_entry = entries.delete { |entry| entry.klass == newklass } || Entry.new(newklass, *args)
+        new_entry = entries.delete_if { |entry| entry.klass == newklass } || Entry.new(newklass, *args)
         i = entries.find_index { |entry| entry.klass == oldklass } || 0
         entries.insert(i, new_entry)
       end
 
       def insert_after(oldklass, newklass, *args)
-        new_entry = entries.delete { |entry| entry.klass == newklass } || Entry.new(newklass, *args)
+        new_entry = entries.delete_if { |entry| entry.klass == newklass } || Entry.new(newklass, *args)
         i = entries.find_index { |entry| entry.klass == oldklass } || entries.count - 1
         entries.insert(i+1, new_entry)
       end