[Event "Interzonal-04"]
[Site "Portoroz"]
[Date "1958.08.06"]
[Round "2"]
[White "De Greif, Boris"]
[Black "Petrosian, Tigran V"]
[Result "1/2-1/2"]

1. Nf3 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. d4 O-O 6. Be2 e5 7. d5 Nbd7 8. Bg5 h6 9. Bh4 a6 10. O-O Qe8 11. Ne1 Nxe4 12. Nxe4 f5 13. Nc3 g5 14. Bg3 f4 15. Bh5 Qe7 16. Ne4 Nc5 17. Bg6 Nxe4 18. Bxe4 g4 19. Nc2 h5 20. h4 Bd7 21. Qd3 fxg3 22. fxg3 Bh6 23. Ne3 Kg7 24. Nf5+ Bxf5 25. Rxf5 Rxf5 26. Bxf5 Qf6 27. Be4 Rf8 28. Qe2 Rf7 29. Rd1 a5 30. b3 1/2-1/2