Let's take a look at the 4th Datu Artur Tan Open 2007 one more time. We've got IM Barlo Nadera (black) against GM Nguyen Dung on white's 25th move. Basically, white doubled up on the knight on a6 but the white knight on c7 is pinned against the queen. This same knight (c7) is protected three times by the bishop on g3, the queen and rook on the c file ( diagram 1). So, here, white played 25. Qe2? The question mark is mine. This move left the rook on c1 unprotected. At this level of competition, I am sure that all sorts of red flags went up in Nadera's mind, and we will see that white might have overlooked a finesse move by his opponent. In response, Nadera moved 25...Nc7. At this very moment, black is a piece up. Recovering the piece does not work because after 26. Bc7 there is the very nice 26...Bd6! Look to the h2 square. Taking this bishop 27. Bd6 will mean 27...Rc1+. Also, 27. g4 is answered by 27...Qh3. And there you see how deep a hole white dug for himself with 25. Qe2. Okay, the game went on via 26. Ra7 Nd5
(diagram 2) with a discov. attack on the white rook. Clearly, 27. Rb7 won't work. White played 27. Rc8 and of course Nadera captured with his bishop 27...Bc8, preserving his piece advantage. Black, ultimately, won this game. I, sometimes, wonder why GMs commit obvious blunders against their equally superior opponents, but they will never make such mistakes against mortals like us. I suppose it takes a good player to make another good player look easy to beat.