diff --git a/lib/webmock/http_lib_adapters/async_http_client_adapter.rb b/lib/webmock/http_lib_adapters/async_http_client_adapter.rb
index 65910901..696752e1 100644
--- a/lib/webmock/http_lib_adapters/async_http_client_adapter.rb
+++ b/lib/webmock/http_lib_adapters/async_http_client_adapter.rb
@@ -35,9 +35,9 @@ module HTTP
       class WebMockClientWrapper < Client
         def initialize(
           endpoint,
-          protocol = endpoint.protocol,
-          scheme = endpoint.scheme,
-          authority = endpoint.authority,
+          protocol: endpoint.protocol,
+          scheme: endpoint.scheme,
+          authority: endpoint.authority,
           **options
         )
           webmock_endpoint = WebMockEndpoint.new(scheme, authority, protocol)
@@ -45,6 +45,7 @@ def initialize(
           @network_client = WebMockClient.new(endpoint, **options)
           @webmock_client = WebMockClient.new(webmock_endpoint, **options)
 
+          @endpoint = endpoint
           @scheme = scheme
           @authority = authority
         end
diff --git a/spec/acceptance/async_http_client/async_http_client_spec.rb b/spec/acceptance/async_http_client/async_http_client_spec.rb
index 43d42464..8b2fd354 100644
--- a/spec/acceptance/async_http_client/async_http_client_spec.rb
+++ b/spec/acceptance/async_http_client/async_http_client_spec.rb
@@ -289,7 +289,7 @@
         subject do
           responses = {}
           Async do |task|
-            Async::HTTP::Client.open(endpoint, protocol) do |client|
+            Async::HTTP::Client.open(endpoint, protocol: protocol) do |client|
               requests_count.times do |index|
                 response = client.get "/foo#{index}"
                 responses[index] = response_to_hash(response)
@@ -316,7 +316,7 @@
         subject do
           responses = {}
           Async do |task|
-            Async::HTTP::Client.open(endpoint, protocol) do |client|
+            Async::HTTP::Client.open(endpoint, protocol: protocol) do |client|
               tasks = requests_count.times.map do |index|
                 task.async do
                   response = client.get "/foo#{index}"
@@ -349,7 +349,7 @@ def make_request(method, url, protocol: nil, headers: {}, body: nil)
         endpoint = Async::HTTP::Endpoint.parse(url)
 
         begin
-          Async::HTTP::Client.open(endpoint, protocol || endpoint.protocol) do |client|
+          Async::HTTP::Client.open(endpoint, protocol: protocol || endpoint.protocol) do |client|
             response = client.send(
               method,
               endpoint.path,