as cPallini says check your return value all the time.
$con = mysql_connect("localhost","root","");
if (!$con)die('Could not connect: ' . mysql_error());
mysql_select_db("tennis", $con);
$ret=mysql_query("INSERT INTO users VALUES ('user', 'password', 'Male', 'full name', 'email@yahoo.com');",$con);
if(!ret)
{
echo mysql_error($con);;
}
mysql_close($con);
?>
a bit suggestion if required also put the name of the fields to confirm your insertion column name