NodeJS Async series not working sequentially

I have the below code,

    var async = require('async'); var rest = require('restler');

    async.series([
        function(callback){
           rest.get('https://api.twitter.com/1.1/statuses/mentions_timeline.json').on('complete', function(result) {
              if (result instanceof Error) {
                console.log('Error:', result);
                this.retry(5000); // try again after 5 sec
              } else {
                console.log(result);
              }         });
            callback(null, 'one');
        },
        function(callback){
            console.log('2nd function');
            callback(null, 'two');
        }
        ],

// optional callback
        function(err, results){
               // results is now equal to ['one', 'two']
               console.log(results);
        });

I am expecting output like this,

{ errors: [ { message: 'Bad Authentication data', code: 215 } ] }
2nd function
[ 'one', 'two' ]

But am getting the below output,

2nd function
[ 'one', 'two' ]
{ errors: [ { message: 'Bad Authentication data', code: 215 } ] }

Rest request output always coming at last. What is the correct way of doing this?