Mocking PutAsJsonAsync in ASP.NET Web API HttpClient

This is a sort of followup to this previous question. I have successfully mocked HttpClient.GetAsync calls, using the technique in the linked question, but when I use the same for PutAsJsonAsync, the response is always null.

response = this.Client.PostAsJsonAsync(url, data).Result;

Any ideas where or indeed what I can Mock in order to change the behaviour as required ?