Saludos
No debes indicar lo alias Cuando pintas los registros
Código PHP:
<?php
$query_toparena = db_query("SELECT arena_team.arenateamid,arena_team.name,arena_team_stats.rating,arena_team_stats.wins2 FROM arena_team LEFT JOIN arena_team_stats ON arena_team.arenateamid = arena_team_stats.arenateamid WHERE arena_team.type=2 ORDER BY arena_team_stats.rating DESC LIMIT 5");
$top_rank = 1;
while($results_toparena=mysqli_fetch_array($query_toparena))
{
echo '<tr><td><b>'.$top_rank++.'.</b></td><td><b>'.$results_toparena["name"].'</b></td><td class="top-rank"><b>'.$results_toparena["rating"].'</b></td><td><b>'.$results_toparena["wins2"].'</b></td></tr>';
}
?>