AylerKupp: <<Pedro Fernandez> 26...Re5 was an easy move to see.>It certainly was for at least both you and Stockfish 10! At d=47 Stockfish considered 26...Re5 to be White's best move, evaluating the resulting position at [+0.31], effectively even. And 26...Re5 was considered its best move 14/40 times from d=8 (35.0%) onwards. But at other depths Stockfish considered as best 26...Bb7 (15 times, 37.5%, last time @ d=43), 26...c4 (9 times, 22.5%, last time @ d=27), 26...Rd4 (once, 2.5%, last time @ d=12), and 26...Rf4 (once, @ d=20).
Of course, this is not a popularity contest, but in addition to 26...Re5, 26...Bb7 and 26...c4 were also considered to be top moves at various times by Stockfish 10, and 26...Bb7 at a relatively high search ply. It was clearly a complex position with several good move possibilities so I wouldn't blame Xiong too much for "failing" to see 26...Re5; he probably saw it but did not consider it to be as good as 26...c4. Which, BTW, is a move I probably would not have considered playing.
Then again 26...c4 is a more double-edged move. Remember that this was the 2nd game of the Standard (Classic) portion of the match and maybe Xiong did not have as much confidence in beating Radjabov in the Rapid and Blitz portions of the match as he did in the Standard portion of the match. Xiong does not have much, if any, top-level experience in Rapid or Blitz games (he's FIDE-unrated at either time control), although he did well against Giri. And Radjabov has extensive experience in Rapid and Blitz-rated games.
If that was the case then <Sally Simpson> would be pleased that Xiong did not play the objectively best move but the move that might give him the best chances to win as Black in this second game. It didn't work this time, but it might work the next time.
Kibitzing
