diff --git a/cli/tests/unit/cache_api_test.ts b/cli/tests/unit/cache_api_test.ts
index 7bc372003a..7bca16d89d 100644
--- a/cli/tests/unit/cache_api_test.ts
+++ b/cli/tests/unit/cache_api_test.ts
@@ -4,6 +4,7 @@ import {
   assertEquals,
   assertFalse,
   assertRejects,
+  assertThrows,
 } from "./test_util.ts";
 
 Deno.test(async function cacheStorage() {
@@ -95,6 +96,13 @@ Deno.test(async function cacheApi() {
   assertFalse(await caches.has(cacheName));
 });
 
+Deno.test(function cacheIllegalConstructor() {
+  // @ts-expect-error illegal constructor
+  assertThrows(() => new Cache(), TypeError, "Illegal constructor");
+  // @ts-expect-error illegal constructor
+  assertThrows(() => new Cache("foo", "bar"), TypeError, "Illegal constructor");
+});
+
 Deno.test(async function cachePutReaderLock() {
   const cacheName = "cache-v1";
   const cache = await caches.open(cacheName);
diff --git a/ext/cache/01_cache.js b/ext/cache/01_cache.js
index afde7f7894..aefd989dd9 100644
--- a/ext/cache/01_cache.js
+++ b/ext/cache/01_cache.js
@@ -33,7 +33,9 @@
         context: "Argument 1",
       });
       const cacheId = await core.opAsync("op_cache_storage_open", cacheName);
-      return new Cache(cacheId);
+      const cache = webidl.createBranded(Cache);
+      cache[_id] = cacheId;
+      return cache;
     }
 
     async has(cacheName) {
@@ -59,18 +61,20 @@
     }
   }
 
+  const _matchAll = Symbol("[[matchAll]]");
   const _id = Symbol("id");
 
   class Cache {
     /** @type {number} */
     [_id];
 
-    constructor(cacheId) {
-      this[_id] = cacheId;
+    constructor() {
+      webidl.illegalConstructor();
     }
 
     /** See https://w3c.github.io/ServiceWorker/#dom-cache-put */
     async put(request, response) {
+      webidl.assertBranded(this, CachePrototype);
       const prefix = "Failed to execute 'put' on 'Cache'";
       webidl.requiredArguments(arguments.length, 2, { prefix });
       request = webidl.converters["RequestInfo_DOMString"](request, {
@@ -159,13 +163,14 @@
 
     /** See https://w3c.github.io/ServiceWorker/#cache-match */
     async match(request, options) {
+      webidl.assertBranded(this, CachePrototype);
       const prefix = "Failed to execute 'match' on 'Cache'";
       webidl.requiredArguments(arguments.length, 1, { prefix });
       request = webidl.converters["RequestInfo_DOMString"](request, {
         prefix,
         context: "Argument 1",
       });
-      const p = await this.#matchAll(request, options);
+      const p = await this[_matchAll](request, options);
       if (p.length > 0) {
         return p[0];
       } else {
@@ -175,6 +180,7 @@
 
     /** See https://w3c.github.io/ServiceWorker/#cache-delete */
     async delete(request, _options) {
+      webidl.assertBranded(this, CachePrototype);
       const prefix = "Failed to execute 'delete' on 'Cache'";
       webidl.requiredArguments(arguments.length, 1, { prefix });
       request = webidl.converters["RequestInfo_DOMString"](request, {
@@ -208,7 +214,7 @@
      *
      * The function will return an array of responses.
      */
-    async #matchAll(request, _options) {
+    async [_matchAll](request, _options) {
       // Step 1.
       let r = null;
       // Step 2.
@@ -273,6 +279,7 @@
   webidl.configurePrototype(CacheStorage);
   webidl.configurePrototype(Cache);
   const CacheStoragePrototype = CacheStorage.prototype;
+  const CachePrototype = Cache.prototype;
 
   let cacheStorage;
   window.__bootstrap.caches = {
diff --git a/tools/wpt/expectation.json b/tools/wpt/expectation.json
index ed43da7e50..d713775d06 100644
--- a/tools/wpt/expectation.json
+++ b/tools/wpt/expectation.json
@@ -4562,8 +4562,6 @@
       "NavigationPreloadManager interface: operation disable()",
       "NavigationPreloadManager interface: operation setHeaderValue(ByteString)",
       "NavigationPreloadManager interface: operation getState()",
-      "Cache interface: existence and properties of interface object",
-      "Cache interface object length",
       "Cache interface: operation match(RequestInfo, optional CacheQueryOptions)",
       "Cache interface: operation matchAll(optional RequestInfo, optional CacheQueryOptions)",
       "Cache interface: operation add(RequestInfo)",
@@ -4652,8 +4650,6 @@
       "NavigationPreloadManager interface: operation disable()",
       "NavigationPreloadManager interface: operation setHeaderValue(ByteString)",
       "NavigationPreloadManager interface: operation getState()",
-      "Cache interface: existence and properties of interface object",
-      "Cache interface object length",
       "Cache interface: operation match(RequestInfo, optional CacheQueryOptions)",
       "Cache interface: operation matchAll(optional RequestInfo, optional CacheQueryOptions)",
       "Cache interface: operation add(RequestInfo)",