diff --git a/radiantcore/map/Map.cpp b/radiantcore/map/Map.cpp
index 9b3e4aabde..07bf7f1a75 100644
--- a/radiantcore/map/Map.cpp
+++ b/radiantcore/map/Map.cpp
@@ -721,6 +721,12 @@ void Map::saveSelected(const std::string& filename, const MapFormatPtr& mapForma
 		format = GlobalMapFormatManager().getMapFormatForFilename(filename);
 	}
 
+    // Fall back to the format of the current map if the selection is empty (#5808)
+    if (!format)
+    {
+        format = getFormat();
+    }
+
     try
     {
         MapResource::saveFile(
@@ -1154,7 +1160,7 @@ void Map::exportSelection(const cmd::ArgumentList& args)
     MapFileSelection fileInfo =
         MapFileManager::getMapFileSelection(false, _("Export selection"), filetype::TYPE_MAP);
 
-	if (!fileInfo.fullPath.empty())
+    if (!fileInfo.fullPath.empty())
 	{
 		GlobalMap().saveSelected(fileInfo.fullPath, fileInfo.mapFormat);
     }
diff --git a/test/MapExport.cpp b/test/MapExport.cpp
index 3bfcc85ab9..af1b3b2ac2 100644
--- a/test/MapExport.cpp
+++ b/test/MapExport.cpp
@@ -289,14 +289,17 @@ brushDef3
     EXPECT_NE(brushTextIndex, std::string::npos) << "Could not locate the exported brush in the expected format";
 }
 
-TEST_F(MapExportTest, ExportSelectedWithEmptyFileExtension)
+namespace
+{
+
+void runExportWithEmptyFileExtension(const std::string& temporaryDataPath,const std::string& command)
 {
     auto brush = algorithm::createCuboidBrush(GlobalMapModule().findOrInsertWorldspawn(),
         AABB(Vector3(0, 0, 0), Vector3(64, 128, 256)), "textures/darkmod/numbers/1");
 
     Node_setSelected(brush, true);
 
-    fs::path tempPath = _context.getTemporaryDataPath();
+    fs::path tempPath = temporaryDataPath;
     tempPath /= "export_empty_file_extension";
     EXPECT_FALSE(fs::exists(tempPath)) << "File already exists";
 
@@ -313,7 +316,7 @@ TEST_F(MapExportTest, ExportSelectedWithEmptyFileExtension)
                 "" // this can happen if e.g. the *.* filter is active
             });
     }));
-    GlobalCommandSystem().executeCommand("SaveSelected");
+    GlobalCommandSystem().executeCommand(command);
 
     EXPECT_TRUE(fs::exists(tempPath)) << "File still doesn't exist";
 
@@ -325,3 +328,15 @@ TEST_F(MapExportTest, ExportSelectedWithEmptyFileExtension)
 }
 
 }
+
+TEST_F(MapExportTest, ExportSelectedWithEmptyFileExtension)
+{
+    runExportWithEmptyFileExtension(_context.getTemporaryDataPath(), "SaveSelected");
+}
+
+TEST_F(MapExportTest, ExportPrefabWithEmptyFileExtension)
+{
+    runExportWithEmptyFileExtension(_context.getTemporaryDataPath(), "SaveSelectedAsPrefab");
+}
+
+}