diff --git a/lib/clock.js b/lib/clock.js
index edd4490..c1192d8 100644
--- a/lib/clock.js
+++ b/lib/clock.js
@@ -1,4 +1,4 @@
-const { debug } = require('node:util');
+const { debug, types } = require('node:util');
 const { validateNumber } = require('./validators');
 
 let debugBench = debug('benchmark', (fn) => {
@@ -199,7 +199,7 @@ const SyncFunction = function () {
 }.constructor;
 
 function createRunner(bench, recommendedCount) {
-  const isAsync = bench.fn.constructor === AsyncFunction;
+  const isAsync = types.isAsyncFunction(bench.fn);
   const hasArg = bench.fn.length >= 1;
 
   if (bench.fn.length > 1) {