I start with the obvious: things are going poorly.
Move to what I think is the problem and ask what their opinion is of what the problem is.
Based on that part of the discussion, I propose a solution.
Of course, I never say the problem is: "you are missing a ton of volleys" or somesuch. If he is missing a ton of volleys, I'll say something like: "I am not hitting good enough groundstrokes and they are teeing off on them towards you." This may or may not be true, but I am not interested in truth, I am interested in winning the match and if throwing myself under the bus will do it, I am fine with that.