[Event "San Antonio IT"]
[Round "4"]
[Site "San Antonio"]
[Date "1972"]
[White "Portisch, Lajos"]
[WhiteElo "2640"]
[Black "Petrosian, Tigran V"]
[BlackElo "2645"]
[Result "1/2-1/2"]
[ECO "A35"]
[Opening "English Opening, Symmetrical"]
 1. c4   c5
 2. Nc3  Nc6
 3. Nf3  g6
 4. e3   Bg7
 5. d4   d6
 6. Be2  cxd4
 7. exd4 Nf6
 8. d5   Nb8
 9. O-O  O-O
10. Be3  Na6
11. Nb5  b6
12. Nfd4 Bb7
13. Bf3  Nd7
14. Qd2  Ne5
15. Be2  Qc8
16. Rac1 Nc5
17. b4   Ne4
18. Qd1  a6
19. Na3  a5
20. b5   Qc7
21. Nc6  Rae8
22. Nb1  Nd7
23. Bf3  Nec5
24. Bg5  e5
25. Be7  f5
26. Bxf8 Nxf8
27. Be2  Bh6
28. Rc2  Bc8
29. Nc3  Nfd7
30. Re1  Nf6
31. Bf1  f4
32. Rce2 Rf8
33. Na4  Nxa4
34. Qxa4 Nd7
35. Ne7+ Kh8
36. Nxc8 Qxc8
37. Qa3  Nc5
38. Qf3  Qf5
39. h3   
1/2-1/2