diff --git a/cmake/QtAutoDetect.cmake b/cmake/QtAutoDetect.cmake
index dd5d8a6bd6..2fa103963a 100644
--- a/cmake/QtAutoDetect.cmake
+++ b/cmake/QtAutoDetect.cmake
@@ -172,8 +172,15 @@ function(qt_auto_detect_cmake_config)
 
         set(CMAKE_TRY_COMPILE_CONFIGURATION "${QT_MULTI_CONFIG_FIRST_CONFIG}" PARENT_SCOPE)
         if(CMAKE_GENERATOR STREQUAL "Ninja Multi-Config")
+            # Create build-<config>.ninja files for all specified configurations.
             set(CMAKE_CROSS_CONFIGS "all" CACHE STRING "")
+
+            # The configuration that will be considered the main one (for example when
+            # configuring standalone tests with a single-config generator like Ninja).
             set(CMAKE_DEFAULT_BUILD_TYPE "${QT_MULTI_CONFIG_FIRST_CONFIG}" CACHE STRING "")
+
+            # By default when ninja is called without parameters, it will build all configurations.
+            set(CMAKE_DEFAULT_CONFIGS "all" CACHE STRING "")
         endif()
     endif()
 endfunction()
diff --git a/cmake/QtPostProcess.cmake b/cmake/QtPostProcess.cmake
index 6d3c4cd240..d1db4686b8 100644
--- a/cmake/QtPostProcess.cmake
+++ b/cmake/QtPostProcess.cmake
@@ -381,7 +381,6 @@ function(qt_generate_build_internals_extra_cmake_code)
 if(QT_BUILD_STANDALONE_TESTS)
     set(CMAKE_BUILD_TYPE \"\${QT_MULTI_CONFIG_FIRST_CONFIG}\" CACHE STRING \"Choose the type of build.\" FORCE)
 endif()\n")
-            string(APPEND QT_EXTRA_BUILD_INTERNALS_VARS "${multi_config_specific}")
         endif()
 
         if(CMAKE_CROSS_CONFIGS)
@@ -392,6 +391,10 @@ endif()\n")
             string(APPEND ninja_multi_config_specific
                 "    set(CMAKE_DEFAULT_BUILD_TYPE \"${CMAKE_DEFAULT_BUILD_TYPE}\" CACHE STRING \"\")\n")
         endif()
+        if(CMAKE_DEFAULT_CONFIGS)
+            string(APPEND ninja_multi_config_specific
+                "    set(CMAKE_DEFAULT_CONFIGS \"${CMAKE_DEFAULT_CONFIGS}\" CACHE STRING \"\")\n")
+        endif()
         if(ninja_multi_config_specific)
             qt_wrap_string_in_if_ninja_multi_config(
                 "${ninja_multi_config_specific}"