It's always bugged me why Janowicz doesn't just hit a normal second serve instead of going all out for the free point so often.
He has hit 9 double faults today and, according to the ATP website, he has hit 244 aces and 191 double faults so far this year, and won 46% of second serve points. Those aren't numbers which suggest taking such a big risk on his second serve so often is paying off for him.
Compare that to the other big fellas:
Raonic: 650 aces, 118 double faults, 54% second serve points won.
Isner: 677 aces, 72 double faults, 57% second serve points won.
Karlovic: 811 aces, 122 double faults, 54% second serve points won.
I know these guys are all better than Jerzy all round this year but his ace/DF ratio looks horrible for a man of his height.