diff --git a/packages/browser/src/node/plugin.ts b/packages/browser/src/node/plugin.ts
index fafa27c51a69..b5fcb2e6ce6b 100644
--- a/packages/browser/src/node/plugin.ts
+++ b/packages/browser/src/node/plugin.ts
@@ -295,8 +295,14 @@ export default (browserServer: BrowserServer, base = '/'): Plugin[] => {
     },
     {
       name: 'vitest:browser:assets',
+      configureServer(server) {
+        server.middlewares.use(
+          '/__vitest__',
+          sirv(resolve(distRoot, 'client/__vitest__')),
+        )
+      },
       resolveId(id) {
-        if (id.startsWith('/__vitest_browser__/') || id.startsWith('/__vitest__/')) {
+        if (id.startsWith('/__vitest_browser__/')) {
           return resolve(distRoot, 'client', id.slice(1))
         }
       },
diff --git a/test/browser/vitest.config.mts b/test/browser/vitest.config.mts
index d51f62255d0c..fd71c6599a3c 100644
--- a/test/browser/vitest.config.mts
+++ b/test/browser/vitest.config.mts
@@ -94,4 +94,14 @@ export default defineConfig({
       BROWSER: browser,
     },
   },
+  plugins: [
+    {
+      name: 'test-no-transform-ui',
+      transform(_code, id, _options) {
+        if (id.includes('/__vitest__/')) {
+          throw new Error(`Unexpected transform: ${id}`)
+        }
+      },
+    },
+  ],
 })