I read on Ayane's blog that someone said Gilles has problem with his arm this year, which gives him trouble with his serve. I guess that would explain some of his really bad services % in some of those matches. Otherwise, I'm really not understanding why he has been serving so badly for a long while now.
It's funny that when the draw came out, we probably all assume he will get Hasse and then Ferrer, turned out he got Schuettler and Karlovic. But Dr. Ivo is really on today, I saw the match, he played really well, although David is not anywhere near his best. So Dr. Ivo is a tough customer despite his ranking atm. Gilles better holds his serve against the serving machine.