Is 16)...Rxg2 Winning?

Tigran Petrosian looked to have a good chance to break Fischer's 19-game winning streak in Game 1 of their Candidates Match to determine the challenger to Spassky - and with the black pieces.

But Petrosian opted not to play 16)...Rxg2. Would it have won?

Kasparov wrote: "It is hard to understand what Petrosian was frightened of. And he himself said: 'Why I didn't play Rxg2, I simply cannot explain.' "

Kasparov says 16)...Rxg2 was the best move and the move actually played was second-rate.

Had a quick look on chesstempo, seems a lot of computer kibitzers give 16...Rxg2 as leading to roughly 0.75 advantage for Black. In a correspondence game from the following year, apparently play continued:

16...Rxg2 17. Qe3 Nd4 18. Kf1 Nxc2 19. Qf3 Rxf2+ 20. Kxf2 Qc5+ 21. Ke2 Qxc4+ 0-1