diff --git a/lib/cache/memory-cache-store.js b/lib/cache/memory-cache-store.js
index af5f14a9fbc..ab8d470eae7 100644
--- a/lib/cache/memory-cache-store.js
+++ b/lib/cache/memory-cache-store.js
@@ -18,7 +18,8 @@ class MemoryCacheStore {
   #maxEntrySize = Infinity
 
   #size = 0
-  #entries = []
+  #count = 0
+  #entries = new Map()
 
   /**
    * @param {import('../../types/cache-interceptor.d.ts').default.MemoryCacheStoreOpts | undefined} [opts]
@@ -73,12 +74,12 @@ class MemoryCacheStore {
       throw new TypeError(`expected key to be object, got ${typeof key}`)
     }
 
+    const topLevelKey = `${key.origin}:${key.path}`
+
     const now = Date.now()
-    return this.#entries.find((entry) => (
+    return this.#entries.get(topLevelKey)?.find((entry) => (
       entry.deleteAt > now &&
       entry.method === key.method &&
-      entry.origin === key.origin &&
-      entry.path === key.path &&
       (entry.vary == null || Object.keys(entry.vary).every(headerName => entry.vary[headerName] === key.headers?.[headerName]))
     ))
   }
@@ -96,6 +97,8 @@ class MemoryCacheStore {
       throw new TypeError(`expected value to be object, got ${typeof val}`)
     }
 
+    const topLevelKey = `${key.origin}:${key.path}`
+
     const store = this
     const entry = { ...key, ...val, body: [], size: 0 }
 
@@ -116,13 +119,25 @@ class MemoryCacheStore {
         callback(null)
       },
       final (callback) {
-        store.#entries.push(entry)
-        store.#size += entry.size
+        let entries = store.#entries.get(topLevelKey)
+        if (!entries) {
+          entries = []
+          store.#entries.set(topLevelKey, entries)
+        }
+        entries.push(entry)
 
-        while (store.#entries.length >= store.#maxCount || store.#size >= store.#maxSize) {
-          const count = Math.max(0, store.#entries.length - store.#maxCount / 2)
-          for (const entry of store.#entries.splice(0, count)) {
-            store.#size -= entry.size
+        store.#size += entry.size
+        store.#count += 1
+
+        if (store.#size > store.#maxSize || store.#count > store.#maxCount) {
+          for (const [key, entries] of store.#entries) {
+            for (const entry of entries.splice(0, entries.length / 2)) {
+              store.#size -= entry.size
+              store.#count -= 1
+            }
+            if (entries.length === 0) {
+              store.#entries.delete(key)
+            }
           }
         }
 
@@ -139,15 +154,13 @@ class MemoryCacheStore {
       throw new TypeError(`expected key to be object, got ${typeof key}`)
     }
 
-    const arr = []
-    for (const entry of this.#entries) {
-      if (entry.path === key.path && entry.origin === key.origin) {
-        this.#size -= entry.size
-      } else {
-        arr.push(entry)
-      }
+    const topLevelKey = `${key.origin}:${key.path}`
+
+    for (const entry of this.#entries.get(topLevelKey) ?? []) {
+      this.#size -= entry.size
+      this.#count -= 1
     }
-    this.#entries = arr
+    this.#entries.delete(topLevelKey)
   }
 }