visayanbraindoctor: The sequence of moves
Nd7? 10. Bxe7 Nxe7 11. Ne5 cxd4?? 12. exd4 Nxe5 13. dxe5
allows Carlsen to plant a pawn on e5 in a French-like semiclosed middlegame. In such a position, if White embarks on a direct Kindside pawn storm, there is little that Black can do about it. I would opine that Xiong got himself into a positionally nearly lost game right in the opening. Carlsen, with his extraordinarily fine technique, almost always has little trouble in converting such positions into a win.
Thus 9.. Nd7? must be a mistake.
After Carlsen occupies the e5 square immediately with
Xiong commits another mistake by playing 11.. cxd4??
12. exd4, we have a French-like semiclosed position with White's e5 pawn permanently cramping Black's Kingside, while Black cannot do his traditional counterplay of c5 (because he has exchanged this pawn already), or f6 (because of the weak b1 - h7 diagonal).
Best thing for Xiong to have done was to maintain the central tension by avoiding the pawn exchange (say by 11... Qb6)
After 11... cxd4 12. exd4 Nxe5 13. dxe5 Black looks positonally lost. (And will most probably lose the game against a player of high caliber such as Carlsen unless unexpected tactical resources are found, as kibitzers above have pointed out.)
Carlsen himself is a wizard at avoiding such positions as he has an extraordinary intuition for positional play. If playing Black, he surely would have declined to play 9.. Nd7? and especially 11.. cxd4??
11.. cxd4?? would probably aghast teachers like Nimzovich who recommended not releasing the central tension in such positions.
Regarding GM Xiong, I know that many Americans see him as another bright hope for the future. But this game, in which he commits basic positional mistakes in the opening to middlegame transition, IMO portends badly for him (unless he learns from it).