Djokovic's opponents in Grand Slam SFs in his early to mid 20s:
Federer, Nadal, Murray, del Potro, Wawrinka, Ferrer, Tsonga
Federer's opponents in Grand Slam SFs in his early to mid 20s:
Kiefer, Grosjean, Henman, Bjorkman aside from his bunnies Hewitt, Roddick and Safin