diff --git a/lib/path.js b/lib/path.js
index f6a2f032230dd2..0dbd2a641c4d89 100644
--- a/lib/path.js
+++ b/lib/path.js
@@ -1281,6 +1281,10 @@ const posix = {
           // We get here if `from` is the exact base path for `to`.
           // For example: from='/foo/bar'; to='/foo/bar/baz'
           return to.slice(i + 2);
+        } else if (fromLen > length && from.charCodeAt(i + 1) === 47/*/*/) {
+          // We get here if `to` is the exact base path for `from`.
+          // For example: from='/foo/bar/baz'; to='/foo/bar'
+          lastCommonSep = i;
         }
         break;
       }
diff --git a/test/parallel/test-path.js b/test/parallel/test-path.js
index aeb6ec0c49bbf7..411231e709861b 100644
--- a/test/parallel/test-path.js
+++ b/test/parallel/test-path.js
@@ -481,7 +481,8 @@ const relativeTests = [
      ['/var/lib', '/var/apache', '../apache'],
      ['/var/', '/var/lib', 'lib'],
      ['/', '/var/lib', 'var/lib'],
-     ['/foo/test', '/foo/test/bar/package.json', 'bar/package.json']
+     ['/foo/test', '/foo/test/bar/package.json', 'bar/package.json'],
+     ['/Users/a/web/b/test/mails', '/Users/a/web/b', '../..']
     ]
   ]
 ];