diff --git a/lib/file-handlers/css.js b/lib/file-handlers/css.js
index 50004a6a..2f4488c0 100644
--- a/lib/file-handlers/css.js
+++ b/lib/file-handlers/css.js
@@ -5,7 +5,7 @@ var utils = require('../utils');
 
 function changeExactlyMatchedUrl (text, oldUrl, newUrl) {
 	// starts with ' " ( ends with ' " )
-	var exactlyMatchedPattern = format('([\'"\(\s])%s([\'"\)\s])', _.escapeRegExp(oldUrl));
+	var exactlyMatchedPattern = format('([\'"\\(\\s])%s([\'"\\)\\s])', _.escapeRegExp(oldUrl));
 	var exactlyMatchedRegexp = new RegExp(exactlyMatchedPattern, 'g');
 	text = text.replace(exactlyMatchedRegexp, function changeUrl (match, g1, g2) {
 		return g1 + newUrl + g2;