diff --git a/src/Symfony/Component/DomCrawler/Crawler.php b/src/Symfony/Component/DomCrawler/Crawler.php
index 6e63d8ea25..790d86a75a 100644
--- a/src/Symfony/Component/DomCrawler/Crawler.php
+++ b/src/Symfony/Component/DomCrawler/Crawler.php
@@ -27,6 +27,11 @@ class Crawler extends \SplObjectStorage
      */
     protected $uri;
 
+    /**
+     * @var string The default namespace prefix to be used with XPath and CSS expressions
+     */
+    private $defaultNamespacePrefix = 'default';
+
     /**
      * Constructor.
      *
@@ -708,6 +713,16 @@ class Crawler extends \SplObjectStorage
         return $form;
     }
 
+    /**
+     * Overloads a default namespace prefix to be used with XPath and CSS expressions.
+     *
+     * @param string $prefix
+     */
+    public function setDefaultNamespacePrefix($prefix)
+    {
+        $this->defaultNamespacePrefix = $prefix;
+    }
+
     /**
      * Converts string for XPath expressions.
      *
@@ -806,7 +821,7 @@ class Crawler extends \SplObjectStorage
 
         foreach ($prefixes as $prefix) {
             // ask for one namespace, otherwise we'd get a collection with an item for each node
-            $namespaces = $domxpath->query(sprintf('(//namespace::*[name()="%s"])[last()]', 'default' === $prefix ? '' : $prefix));
+            $namespaces = $domxpath->query(sprintf('(//namespace::*[name()="%s"])[last()]', $this->defaultNamespacePrefix === $prefix ? '' : $prefix));
             if ($node = $namespaces->item(0)) {
                 $domxpath->registerNamespace($prefix, $node->nodeValue);
             } else {
@@ -824,7 +839,7 @@ class Crawler extends \SplObjectStorage
      */
     private function findNamespacePrefixes($xpath)
     {
-        if (preg_match_all('/(?P<prefix>[a-zA-Z_][a-zA-Z_0-9\-\.]+):[^:]/', $xpath, $matches)) {
+        if (preg_match_all('/(?P<prefix>[a-zA-Z_][a-zA-Z_0-9\-\.]*):[^:]/', $xpath, $matches)) {
             return array_unique($matches['prefix']);
         }
 
diff --git a/src/Symfony/Component/DomCrawler/Tests/CrawlerTest.php b/src/Symfony/Component/DomCrawler/Tests/CrawlerTest.php
index cca6165fc2..54760b7bed 100644
--- a/src/Symfony/Component/DomCrawler/Tests/CrawlerTest.php
+++ b/src/Symfony/Component/DomCrawler/Tests/CrawlerTest.php
@@ -378,6 +378,16 @@ EOF
         $this->assertSame('tag:youtube.com,2008:video:kgZRZmEc9j4', $crawler->text());
     }
 
+    public function testFilterXPathWithCustomDefaultNamespace()
+    {
+        $crawler = $this->createTestXmlCrawler();
+        $crawler->setDefaultNamespacePrefix('x');
+        $crawler = $crawler->filterXPath('//x:entry/x:id');
+
+        $this->assertCount(1, $crawler, '->filterXPath() automatically registers a namespace');
+        $this->assertSame('tag:youtube.com,2008:video:kgZRZmEc9j4', $crawler->text());
+    }
+
     public function testFilterXPathWithNamespace()
     {
         $crawler = $this->createTestXmlCrawler()->filterXPath('//yt:accessControl');