I was watching Justine Henin playing against Roberta Vinci earlier in the second match at the Unicef Open. Henin won in straight sets, 6-3, 6-3.
The one thing I caught from the match is Henin's serve going nutty when she is nervous. She tends to miss the first serve and then double faults when she is nervous.
This is something you don't expect from her, but the comeback has only been about six months so maybe she'll find a way to fight her nerves.