diff --git a/app.js b/app.js
index 8db2b1d..61f9c5b 100644
--- a/app.js
+++ b/app.js
@@ -344,6 +344,7 @@ client.on('connection', function (clientSpark)
 
 	clientSpark.on('client-pong', function (data)
 	{
+		var serverTime = _.get(data, "serverTime", 0);
 		var latency = Math.ceil( (_.now() - data.serverTime) / 2 );
 
 		clientSpark.emit('client-latency', { latency: latency });