Yes, it shows that you should never underestimate your opponent ... especially with black. Carlsen obviously went for a very complicated middle game just for the sake of getting complications, and it backfired pretty badly.
CThinker wrote:And Nakamura, playing Black, held off Anand to a very nice draw.
And in the second round beaten Kramnik with black.
Kramnik sacrificed a minor piece for attack on the Black king and advanced development. I think it was dubious because they traded Queens just a few moves later. The attack became unsustainable.
