Index: wp-includes/meta.php
===================================================================
--- wp-includes/meta.php	(revision 17724)
+++ wp-includes/meta.php	(working copy)
@@ -400,7 +400,7 @@
 	 * @since 3.2
 	 * @access public
 	 * @var string
-	 */	
+	 */
 	public $relation;
 
 	/**
@@ -420,12 +420,20 @@
 
 		$this->queries = array();
 
-		foreach ( $meta_query as $key => $query ) {
+		foreach ( $meta_query as $query ) {
 			if ( ! is_array( $query ) )
 				continue;
 
 			$this->queries[] = $query;
 		}
+
+		// Compat
+		if( empty( $this->queries ) ) {
+			foreach( array( 'key', 'value', 'compare', 'type' ) as $key ) {
+				if ( isset( $meta_query[$key] ) )
+					$this->queries[0][$key] = $meta_query[$key];
+			}
+		}
 	}
 
 	/**