diff --git a/packages/browser/src/client/logger.ts b/packages/browser/src/client/logger.ts
index c65eaa3f3290..8a4e615f0ea4 100644
--- a/packages/browser/src/client/logger.ts
+++ b/packages/browser/src/client/logger.ts
@@ -3,8 +3,8 @@ import { importId } from './utils'
 
 const { Date, console } = globalThis
 
-export async function setupConsoleLogSpy() {
-  const { stringify, format, inspect } = await importId('vitest/utils') as typeof import('vitest/utils')
+export async function setupConsoleLogSpy(basePath: string) {
+  const { stringify, format, inspect } = await importId('vitest/utils', basePath) as typeof import('vitest/utils')
   const { log, info, error, dir, dirxml, trace, time, timeEnd, timeLog, warn, debug, count, countReset } = console
   const formatInput = (input: unknown) => {
     if (input instanceof Node)
diff --git a/packages/browser/src/client/main.ts b/packages/browser/src/client/main.ts
index 1e8420e0867b..61ec052e4ec7 100644
--- a/packages/browser/src/client/main.ts
+++ b/packages/browser/src/client/main.ts
@@ -3,7 +3,7 @@ import type { ResolvedConfig } from 'vitest'
 import type { CancelReason, VitestRunner } from '@vitest/runner'
 import type { VitestExecutor } from '../../../vitest/src/runtime/execute'
 import { createBrowserRunner } from './runner'
-import { importId } from './utils'
+import { importId as importIdImpl } from './utils'
 import { setupConsoleLogSpy } from './logger'
 import { createSafeRpc, rpc, rpcDone } from './rpc'
 import { setupDialogsSpy } from './dialog'
@@ -24,6 +24,10 @@ const url = new URL(location.href)
 const testId = url.searchParams.get('id') || 'unknown'
 const reloadTries = Number(url.searchParams.get('reloadTries') || '0')
 
+const basePath = () => config!.base! || '/'
+const importId = (id: string) => importIdImpl(id, basePath())
+const viteClientPath = () => `${basePath()}@vite/client`
+
 function getQueryPaths() {
   return url.searchParams.getAll('path')
 }
@@ -181,15 +185,14 @@ ws.addEventListener('open', async () => {
   const iFrame = document.getElementById('vitest-ui') as HTMLIFrameElement
   iFrame.setAttribute('src', '/__vitest__/')
 
-  await setupConsoleLogSpy()
+  await setupConsoleLogSpy(basePath())
   setupDialogsSpy()
   await runTests(paths, config!)
 })
 
 async function prepareTestEnvironment(config: ResolvedConfig) {
   // need to import it before any other import, otherwise Vite optimizer will hang
-  const viteClientPath = '/@vite/client'
-  await import(viteClientPath)
+  await import(viteClientPath())
 
   const {
     startTests,
@@ -204,7 +207,7 @@ async function prepareTestEnvironment(config: ResolvedConfig) {
 
   if (!runner) {
     const { VitestTestRunner } = await importId('vitest/runners') as typeof import('vitest/runners')
-    const BrowserRunner = createBrowserRunner(VitestTestRunner, { takeCoverage: () => takeCoverageInsideWorker(config.coverage, executor) })
+    const BrowserRunner = createBrowserRunner(VitestTestRunner, { takeCoverage: () => takeCoverageInsideWorker(config.coverage, executor) }, basePath())
     runner = new BrowserRunner({ config, browserHashMap })
   }
 
diff --git a/packages/browser/src/client/runner.ts b/packages/browser/src/client/runner.ts
index cfa79438d840..4b00a5f24c97 100644
--- a/packages/browser/src/client/runner.ts
+++ b/packages/browser/src/client/runner.ts
@@ -14,6 +14,7 @@ interface CoverageHandler {
 export function createBrowserRunner(
   original: { new(config: ResolvedConfig): VitestRunner },
   coverageModule: CoverageHandler | null,
+  basePath: string,
 ): { new(options: BrowserRunnerOptions): VitestRunner } {
   return class BrowserTestRunner extends original {
     public config: ResolvedConfig
@@ -71,9 +72,9 @@ export function createBrowserRunner(
       }
 
       // on Windows we need the unit to resolve the test file
-      const importpath = /^\w:/.test(filepath)
-        ? `/@fs/${filepath}?${test ? 'browserv' : 'v'}=${hash}`
-        : `${filepath}?${test ? 'browserv' : 'v'}=${hash}`
+      const prefix = `${basePath}${/^\w:/.test(filepath) ? '@fs/' : ''}`
+      const query = `${test ? 'browserv' : 'v'}=${hash}`
+      const importpath = `${prefix}${filepath}?${query}`.replace(/\/+/g, '/')
       await import(importpath)
     }
   }
diff --git a/packages/browser/src/client/utils.ts b/packages/browser/src/client/utils.ts
index 27a390af601d..a4c1a856117f 100644
--- a/packages/browser/src/client/utils.ts
+++ b/packages/browser/src/client/utils.ts
@@ -1,5 +1,5 @@
-export async function importId(id: string) {
-  const name = `/@id/${id}`
+export async function importId(id: string, basePath: string) {
+  const name = `${basePath}@id/${id}`
   // @ts-expect-error mocking vitest apis
   return __vi_wrap_module__(import(name))
 }
diff --git a/test/browser/specs/fix-4686.test.mjs b/test/browser/specs/fix-4686.test.mjs
new file mode 100644
index 000000000000..9caf2d4169e0
--- /dev/null
+++ b/test/browser/specs/fix-4686.test.mjs
@@ -0,0 +1,18 @@
+import assert from 'node:assert'
+import test from 'node:test'
+import runVitest from './run-vitest.mjs'
+
+const {
+  stderr,
+  browserResultJson,
+  passedTests,
+  failedTests,
+} = await runVitest(['--config', 'vitest.config-basepath.mts'])
+
+await test('tests run in presence of config.base', async () => {
+  assert.ok(browserResultJson.testResults.length === 8, 'Not all the tests have been run')
+  assert.ok(passedTests.length === 7, 'Some tests failed')
+  assert.ok(failedTests.length === 1, 'Some tests have passed but should fail')
+
+  assert.doesNotMatch(stderr, /Unhandled Error/, 'doesn\'t have any unhandled errors')
+})
diff --git a/test/browser/vitest.config-basepath.mts b/test/browser/vitest.config-basepath.mts
new file mode 100644
index 000000000000..360753c0586d
--- /dev/null
+++ b/test/browser/vitest.config-basepath.mts
@@ -0,0 +1,4 @@
+import { defineConfig, mergeConfig } from 'vitest/config'
+import baseConfig from './vitest.config.mts'
+
+export default mergeConfig(baseConfig, defineConfig({ base: '/fix-4686' }))