Does it not fit because there is a small ridge on one side of the connector (usually referred to as a key). If that is the case just cut that portion off.
That ridge is there to make sure you plug it in the right way round so pay attention to how you hook it up to your Rx. In the Spektrum the orange should be "S" the red should be "+" and the brown should be "-".
I had to do that with my 1/16 slash, the stock Traxxas plugs would not fit in my SR300. I trimmed them with a pair of flush cutters and voila.
I just peeked at a picture of the ESC and It looks like it should work.
Star