Going back three years earlier to the 1970 Siegen Chess Olympics he defeated GM Vastimil Hort. Hort may never have been world champion, but in 1970 his rating was over 2700 and he was ranked just outside the world's top ten and was one of the best players in the world outside the Soviet Union. In the USSR vs. Rest of the World match in 1970 Hort played fourth board (behind Larsen, Fischer and Portisch) for the World team and scored +1 -0 =3 against Lev Polugaevsky. Tan's rating was a modest 2300-plus.
After reading in the Olimpbase article that Tan "destroyed" Hort I was expecting a crushing win by Tan, but while analyzing the game, which by the way was just as complex as the one against Smyslov, when I got to Hort's resignation it looked like something was wrong. Tan did have a win, but his 24th move appears to have thrown it away. Both Stockfish and Komodo 8 were showing the position was equal. I thought maybe there were more moves played and the game score was incomplete, but after checking several sources it was clear that Hort did resign after Tan's 33.Re3.
Thinking that the engines might be missing something, it was time to run some Shootouts using Stockfish and Komodo 8 set at 15-23 plies. Stockfish scored 5 draws and white's result using Komodo 8 was +0 -1 =4. So, Stockfish was left to analyze the final position while I went off to do something else. After 30 minutes its evaluation was 0.00!
The only conclusion that I can draw is that Hort's resignation was premature and that would make Tan's loss to Smyslov three years later poetic justice! Can anybody demonstrate a win for white in the final position or offer an explanation for Hort's resignation?