[Event "Interzonal-09b"]
[Site "Petropolis"]
[Date "1973.08.11"]
[Round "13"]
[White "Portisch, Lajos"]
[Black "Biyiasas, Peter"]
[Result "1-0"]
1. d4 g6 2. c4 d6 3. Nc3 Bg7 4. e4 e5 5. d5 Qe7 6. Be2 Bh6 7. Bxh6 Nxh6 8. Qd2 Ng4 9. h3 Nf6 10. Nf3 O-O 11. Nh2 Nbd7 12. Qe3 a5 13. g4 Nc5 14. O-O-O Ne8 15. Rdf1 Ng7 16. Bd1 Bd7 17. Bc2 Rae8 18. f4 f5 19. fxe5 Qxe5 20. Nf3 f4 21. Nxe5 fxe3 22. Nxd7 Nxd7 23. Ba4 Re7 24. Bxd7 Rxd7 25. Rxf8+ Kxf8 26. Rf1+ Rf7 27. Rxf7+ Kxf7 28. Kd1 Kf6 29. Ke2 Kg5 30. Kxe3 Kh4 31. Nb5 Kxh3 32. Nxc7 Kxg4 33. c5 Kg5 34. cxd6 Kf6 35. e5+ Kf7 36. Kf4 Nf5 37. e6+ Kf8 38. e7+ 1-0