LOL, how does continents fit into how impressive it is?
Or how long? Nadal's clay streak lasted from 10 Apr - 6 Jun 2010, that's a 56 day span. He played 4 tourneys, MC,Rome,Madrid,RG. Nadal won 3 MS + 1 GS.
Djoker's HC streak started 17 January - 4th April 2011, 76 days.
Djoker also played 4 tourneys, AO,Dubai,IW,Miami. Djoker won 2 MS + 1 GS + 1 500 event.
I don't get the more varied conditions for Djoker. IW and AO play pretty much the same court wise, only it's a bit more windy in IW and Miami is also slow HC, only with a more sandpaper'ish feel.
For Nadal's streak he also has windy conditions in MC depending on the day(see this year in Ljubicic match for examle) and the clay speed differs quite a bit, MC being molases slow, Rome and Madrid being faster and RG falling somewhere in between.
As for the nr.1 bit. The saying goes that Nadal was beating Fed(in Madrid),a nr.1 whose worse surface is clay. Ok. Well, turns out that Djoker beat in his streak Nadal twice, whose worse surface is HC. Imagine that.
Nadal had to beat hyped up nightmare soderling in RG final(imagine the pressure for a loss there), in straights no less and took revenge on Fed in Madrid. Not to mention the HUGE pressure he had coming in(plus his form at the time was questionable and he had knee problems in Miami)to defend, not having won a title in like 11 months whereas Nole came into his streak with no little to no pressure(pressure was on Rafa in AO 2011) with a mental boom after winning DC.