diff --git a/libs/gst/base/gstaggregator.c b/libs/gst/base/gstaggregator.c
index e2e2ec7604..06f362ac51 100644
--- a/libs/gst/base/gstaggregator.c
+++ b/libs/gst/base/gstaggregator.c
@@ -1669,14 +1669,22 @@ gst_aggregator_default_create_new_pad (GstAggregator * self,
 
   GST_OBJECT_LOCK (self);
   if (req_name == NULL || strlen (req_name) < 6
-      || !g_str_has_prefix (req_name, "sink_")) {
+      || !g_str_has_prefix (req_name, "sink_")
+      || strrchr (req_name, '%') != NULL) {
     /* no name given when requesting the pad, use next available int */
     serial = ++priv->max_padserial;
   } else {
+    gchar *endptr = NULL;
+
     /* parse serial number from requested padname */
-    serial = g_ascii_strtoull (&req_name[5], NULL, 10);
-    if (serial > priv->max_padserial)
-      priv->max_padserial = serial;
+    serial = g_ascii_strtoull (&req_name[5], &endptr, 10);
+    if (endptr != NULL && *endptr == '\0') {
+      if (serial > priv->max_padserial) {
+        priv->max_padserial = serial;
+      }
+    } else {
+      serial = ++priv->max_padserial;
+    }
   }
 
   name = g_strdup_printf ("sink_%u", serial);