diff --git a/packages/next/build/webpack/loaders/next-serverless-loader.ts b/packages/next/build/webpack/loaders/next-serverless-loader.ts
index 69885cff071c4..e68b65b11b536 100644
--- a/packages/next/build/webpack/loaders/next-serverless-loader.ts
+++ b/packages/next/build/webpack/loaders/next-serverless-loader.ts
@@ -72,9 +72,9 @@ const nextServerlessLoader: loader.Loader = function () {
     `
     : ''
 
-  const collectDynamicRouteParams = pageIsDynamicRoute
+  const normalizeDynamicRouteParams = pageIsDynamicRoute
     ? `
-      function collectDynamicRouteParams(query) {
+      function normalizeDynamicRouteParams(query) {
         return Object.keys(defaultRouteRegex.groups)
           .reduce((prev, key) => {
             let value = query[key]
@@ -84,7 +84,14 @@ const nextServerlessLoader: loader.Loader = function () {
               // non-provided optional values should be undefined so normalize
               // them to undefined
             }
-            if(defaultRouteRegex.groups[key].optional && !value) {
+            if(
+              defaultRouteRegex.groups[key].optional &&
+              (!value || (
+                Array.isArray(value) &&
+                value.length === 1 &&
+                value[0] === 'index'
+              ))
+            ) {
               value = undefined
               delete query[key]
             }
@@ -223,7 +230,7 @@ const nextServerlessLoader: loader.Loader = function () {
 
       ${defaultRouteRegex}
 
-      ${collectDynamicRouteParams}
+      ${normalizeDynamicRouteParams}
 
       ${handleRewrites}
 
@@ -241,9 +248,11 @@ const nextServerlessLoader: loader.Loader = function () {
           const params = ${
             pageIsDynamicRoute
               ? `
-              trustQuery
-                ? collectDynamicRouteParams(parsedUrl.query)
-                : dynamicRouteMatcher(parsedUrl.pathname)
+              normalizeDynamicRouteParams(
+                trustQuery
+                  ? parsedUrl.query
+                  : dynamicRouteMatcher(parsedUrl.pathname)
+              )
               `
               : `{}`
           }
@@ -316,7 +325,7 @@ const nextServerlessLoader: loader.Loader = function () {
 
     ${dynamicRouteMatcher}
     ${defaultRouteRegex}
-    ${collectDynamicRouteParams}
+    ${normalizeDynamicRouteParams}
     ${handleRewrites}
 
     export const config = ComponentInfo['confi' + 'g'] || {}
@@ -394,9 +403,11 @@ const nextServerlessLoader: loader.Loader = function () {
               !getStaticProps &&
               !getServerSideProps
             ) ? {}
-              : trustQuery
-                ? collectDynamicRouteParams(parsedUrl.query)
-                : dynamicRouteMatcher(parsedUrl.pathname) || {};
+              : normalizeDynamicRouteParams(
+                trustQuery
+                  ? parsedUrl.query
+                  : dynamicRouteMatcher(parsedUrl.pathname)
+              )
             `
             : `const params = {};`
         }
@@ -433,6 +444,7 @@ const nextServerlessLoader: loader.Loader = function () {
           `
             : `const nowParams = null;`
         }
+
         // make sure to set renderOpts to the correct params e.g. _params
         // if provided from worker or params if we're parsing them here
         renderOpts.params = _params || params
diff --git a/test/integration/root-optional-revalidate/pages/[[...slug]].js b/test/integration/root-optional-revalidate/pages/[[...slug]].js
new file mode 100644
index 0000000000000..4b80b91607436
--- /dev/null
+++ b/test/integration/root-optional-revalidate/pages/[[...slug]].js
@@ -0,0 +1,24 @@
+export default function Home(props) {
+  return <pre id="props">{JSON.stringify(props)}</pre>
+}
+
+export async function getStaticPaths() {
+  return {
+    paths: [
+      { params: { slug: false } },
+      { params: { slug: ['a'] } },
+      { params: { slug: ['hello', 'world'] } },
+    ],
+    fallback: false,
+  }
+}
+
+export async function getStaticProps({ params }) {
+  return {
+    props: {
+      params,
+      random: Math.random(),
+    },
+    revalidate: 1,
+  }
+}
diff --git a/test/integration/root-optional-revalidate/server.js b/test/integration/root-optional-revalidate/server.js
new file mode 100644
index 0000000000000..aa513c139e055
--- /dev/null
+++ b/test/integration/root-optional-revalidate/server.js
@@ -0,0 +1,27 @@
+const path = require('path')
+const http = require('http')
+
+const server = http.createServer(async (req, res) => {
+  const render = async (page) => {
+    const mod = require(`./${path.join('.next/serverless/pages/', page)}`)
+    try {
+      return await (mod.render || mod.default || mod)(req, res)
+    } catch (err) {
+      res.statusCode = 500
+      return res.end('internal error')
+    }
+  }
+
+  try {
+    await render('/[[...slug]].js')
+  } catch (err) {
+    console.error('failed to render', err)
+    res.statusCode = 500
+    res.end('Internal Error')
+  }
+})
+
+const port = process.env.PORT || 3000
+server.listen(port, () => {
+  console.log('ready on', port)
+})
diff --git a/test/integration/root-optional-revalidate/test/index.test.js b/test/integration/root-optional-revalidate/test/index.test.js
new file mode 100644
index 0000000000000..75e453057ae51
--- /dev/null
+++ b/test/integration/root-optional-revalidate/test/index.test.js
@@ -0,0 +1,115 @@
+/* eslint-env jest */
+
+import { join } from 'path'
+import cheerio from 'cheerio'
+import {
+  killApp,
+  findPort,
+  File,
+  nextBuild,
+  nextStart,
+  initNextServerScript,
+  renderViaHTTP,
+  waitFor,
+} from 'next-test-utils'
+
+jest.setTimeout(1000 * 60 * 2)
+
+const appDir = join(__dirname, '../')
+const nextConfig = new File(join(appDir, 'next.config.js'))
+let app
+let appPort
+
+const getProps = async (path, expected) => {
+  const html = await renderViaHTTP(appPort, path)
+  const $ = cheerio.load(html)
+  return JSON.parse($('#props').text())
+}
+
+const runTests = (rawServerless = false) => {
+  it('should render / correctly', async () => {
+    const props = await getProps('/', { params: {} })
+    expect(props.params).toEqual({})
+
+    await waitFor(1000)
+    await getProps('/')
+
+    const newProps = await getProps('/', { params: {} })
+    expect(newProps.params).toEqual({})
+    expect(props.random).not.toBe(newProps.random)
+  })
+
+  if (rawServerless) {
+    it('should render /index correctly', async () => {
+      const props = await getProps('/index')
+      expect(props.params).toEqual({})
+
+      await waitFor(1000)
+      await getProps('/index')
+
+      const newProps = await getProps('/index')
+      expect(newProps.params).toEqual({})
+      expect(props.random).not.toBe(newProps.random)
+    })
+  }
+
+  it('should render /a correctly', async () => {
+    const props = await getProps('/a')
+    expect(props.params).toEqual({ slug: ['a'] })
+
+    await waitFor(1000)
+    await getProps('/a')
+
+    const newProps = await getProps('/a')
+    expect(newProps.params).toEqual({ slug: ['a'] })
+    expect(props.random).not.toBe(newProps.random)
+  })
+
+  it('should render /hello/world correctly', async () => {
+    const props = await getProps('/hello/world')
+    expect(props.params).toEqual({ slug: ['hello', 'world'] })
+
+    await waitFor(1000)
+    await getProps('/hello/world')
+
+    const newProps = await getProps('/hello/world')
+    expect(newProps.params).toEqual({ slug: ['hello', 'world'] })
+    expect(props.random).not.toBe(newProps.random)
+  })
+}
+
+describe('Root Optional Catch-all Revalidate', () => {
+  describe('production mode', () => {
+    beforeAll(async () => {
+      await nextBuild(appDir)
+      appPort = await findPort()
+      app = await nextStart(appDir, appPort)
+    })
+    afterAll(() => killApp(app))
+
+    runTests()
+  })
+
+  describe('raw serverless mode', () => {
+    beforeAll(async () => {
+      nextConfig.write(`
+        module.exports = {
+          target: 'experimental-serverless-trace'
+        }
+      `)
+      await nextBuild(appDir)
+      appPort = await findPort()
+
+      app = await initNextServerScript(join(appDir, 'server.js'), /ready on/i, {
+        ...process.env,
+        PORT: appPort,
+      })
+    })
+    afterAll(async () => {
+      nextConfig.delete()
+      await killApp(app)
+    })
+
+    runTests(true)
+  })
+})