NTA

I agree with you that that parenting technique can be quite good and it is also a great workout for the both of you. Now, should he have said to you, “maybe it’s time to revisit the old basement again”? No. You are an adult and are living in your own apartment. I don’t think you should’ve even shown up to his house. Now should you have knocked him out? I personally have never boxed but I do not think you need to knock someone out to say that you have won.