diff --git a/src/connection-pool.js b/src/connection-pool.js
index 5abcddc84..61bdb9bed 100644
--- a/src/connection-pool.js
+++ b/src/connection-pool.js
@@ -288,7 +288,7 @@ ConnectionPool.prototype.createMessage = function(connectionId, resp) {
   var milliseconds = parseInt(pt.nanos, 10) / 1e6;
   var originalDataLength = resp.message.data.length;
 
-  return {
+  var message = {
     connectionId: connectionId,
     ackId: resp.ackId,
     id: resp.message.messageId,
@@ -300,13 +300,14 @@ ConnectionPool.prototype.createMessage = function(connectionId, resp) {
     get length() {
       return originalDataLength;
     },
-    ack: function() {
-      self.subscription.ack_(this);
-    },
-    nack: function() {
-      self.subscription.nack_(this);
-    },
   };
+  message.ack = function() {
+    self.subscription.ack_(message);
+  };
+  message.nack = function() {
+    self.subscription.nack_(message);
+  };
+  return message;
 };
 
 /*!