I don't know, I think Sayaka got to her in the shouting department, Think Saina came across as a bit mentally weak. Not enough for her to lose though well done Saina
The match didn't have my complete attention so I didn't really pick up on it too much. However there was a rally in the second game when Saina played a net shot return into the net and Sayaka screamed in her face, the next point the reverse happened and Saina screamed back at her. It did seem like a reaction born from aggravation, not sure I'd classify it as mental weakness though.