diff --git a/cli.js b/cli.js
index b13782214..ed4281b78 100755
--- a/cli.js
+++ b/cli.js
@@ -1,5 +1,12 @@
 #!/usr/bin/env node
 'use strict';
+
+var debug = require('debug')('ava');
+
+if (debug.enabled) {
+	require('time-require');
+}
+
 var fs = require('fs');
 var path = require('path');
 var figures = require('figures');
@@ -109,6 +116,12 @@ function run(file) {
 		args.push('--serial');
 	}
 
+	// Forward the `time-require` `--sorted` flag.
+	// Intended for internal optimization tests only.
+	if (cli.flags.sorted) {
+		args.push('--sorted');
+	}
+
 	return fork(args)
 		.on('stats', stats)
 		.on('test', test)
diff --git a/lib/babel.js b/lib/babel.js
index 46fbc9ceb..2cc6359a5 100644
--- a/lib/babel.js
+++ b/lib/babel.js
@@ -1,5 +1,11 @@
 'use strict';
 
+var debug = require('debug')('ava');
+
+if (debug.enabled) {
+	require('time-require');
+}
+
 // Bind globals first, before anything has a chance to interfere.
 var globals = require('./globals');
 
diff --git a/package.json b/package.json
index 045b23201..0473b8d47 100644
--- a/package.json
+++ b/package.json
@@ -109,6 +109,7 @@
     "set-immediate-shim": "^1.0.1",
     "source-map-support": "^0.3.3",
     "squeak": "^1.2.0",
+    "time-require": "^0.1.2",
     "update-notifier": "^0.5.0"
   },
   "devDependencies": {