diff --git a/core/audits/byte-efficiency/legacy-javascript.js b/core/audits/byte-efficiency/legacy-javascript.js
index df5e023b8cf9..f870062d7ec3 100644
--- a/core/audits/byte-efficiency/legacy-javascript.js
+++ b/core/audits/byte-efficiency/legacy-javascript.js
@@ -152,6 +152,12 @@ class LegacyJavascript extends ByteEfficiencyAudit {
     // Object.defineProperty(String.prototype, 'startsWith'
     expression += `|defineProperty\\(${object || 'window'},\\s?${qt(property)}`;
 
+    // es-shims
+    // no(Object,{entries:r},{entries:function
+    if (object) {
+      expression += `|\\(${object},\\s*{${property}:.*},\\s*{${property}`;
+    }
+
     // core-js
     if (object) {
       const objectWithoutPrototype = object.replace('.prototype', '');
@@ -234,6 +240,9 @@ class LegacyJavascript extends ByteEfficiencyAudit {
     ];
 
     for (const [name, coreJs2Module] of coreJsPolyfills) {
+      // es-shims follows a pattern for its packages.
+      // Tack it onto the corejs size estimation, as it is likely close in size.
+      const esShimModule = name.toLowerCase();
       data.push({
         name,
         modules: [
@@ -243,6 +252,7 @@ class LegacyJavascript extends ByteEfficiencyAudit {
             .replace('es6.', 'es.')
             .replace('es7.', 'es.')
             .replace('typed.', 'typed-array.'),
+          esShimModule,
         ],
         corejs: true,
       });
@@ -333,8 +343,9 @@ class LegacyJavascript extends ByteEfficiencyAudit {
           // Skip if the pattern matching found a match for this polyfill.
           if (matches.some(m => m.name === name)) continue;
 
-          const source = bundle.rawMap.sources.find(source =>
-            modules.some(module => source.endsWith(`${module}.js`)));
+          const source = bundle.rawMap.sources.find(source => modules.some(module => {
+            return source.endsWith(`/${module}.js`) || source.includes(`node_modules/${module}/`);
+          }));
           if (!source) continue;
 
           const mapping = bundle.map.mappings().find(m => m.sourceURL === source);
diff --git a/core/test/audits/byte-efficiency/legacy-javascript-test.js b/core/test/audits/byte-efficiency/legacy-javascript-test.js
index c1d7d8259fb2..6903b896138d 100644
--- a/core/test/audits/byte-efficiency/legacy-javascript-test.js
+++ b/core/test/audits/byte-efficiency/legacy-javascript-test.js
@@ -176,6 +176,9 @@ describe('LegacyJavaScript audit', () => {
       'Object.defineProperty(String.prototype, "repeat", function() {})',
       '$export($export.S,"Object",{values:function values(t){return i(t)}})',
       'String.raw = function() {}',
+      // es-shims (object.entries)
+      'no(Object,{entries:r},{entries:function',
+      'no(Array.prototype,{find:r},{find:function',
       // Currently are no polyfills that declare a class. Maybe in the future.
       // 'Object.defineProperty(window, \'WeakMap\', function() {})',
       // 'WeakMap = function() {}',
@@ -255,7 +258,11 @@ describe('LegacyJavaScript audit', () => {
 
   it('detects non-corejs modules from source maps', async () => {
     const map = {
-      sources: ['node_modules/focus-visible/dist/focus-visible.js'],
+      sources: [
+        'node_modules/focus-visible/dist/focus-visible.js',
+        'node_modules/array.prototype.find/index.js',
+        'node_modules/object.entries/index.js',
+      ],
       mappings: 'blah',
     };
     const script = {
@@ -266,13 +273,22 @@ describe('LegacyJavaScript audit', () => {
     const result = await getResult([script]);
 
     expect(result.items).toHaveLength(1);
+    expect(result.items[0].subItems.items).toHaveLength(3);
     expect(result.items[0].subItems.items).toMatchObject([
       {
         signal: 'focus-visible',
         location: {line: 0, column: 0},
       },
+      {
+        signal: 'Array.prototype.find',
+        location: {line: 0, column: 0},
+      },
+      {
+        signal: 'Object.entries',
+        location: {line: 0, column: 0},
+      },
     ]);
-    expect(result.items[0].wastedBytes).toBe(3000);
+    expect(result.items[0].wastedBytes).toBe(38062);
   });
 });