When you think of a Rihanna performance, you think dynamic, flashy and fun. This was not that. Her version of “Stay,” featuring Mikky Ekko (who wore a black knit ski cap for the occasion) was redolent and sultry and sleepy. The song did a remarkable job of reminding viewers that Rihanna has a truly beautiful voice and is far from simply being a manufactured product. Unfortunately, her performance was slower than the plot in Battleship.