We can see Gaga smiling and clapping her hands at 0:22 and this is the reaction RIGHT after he won, then she was talking to Diane not caring about Sam going to the stage at 0:28 and the reaction which we all saw (0:55) was when he mentioned her in his speech. I think she was happy for him and surprised at the same time. We can see Diane and that woman sitting next to her (is that Catherine Hardewick?) are very disappointed.  Taylor rocks