Round 1 Petrosian vs Portisch, 1974 (E17) Queen's Indian, 18 moves, 1/2-1/2 Round 2 Portisch vs Petrosian, 1974  (B39) Sicilian, Accelerated Fianchetto, Breyer Variation, 40 moves, 1/2-1/2 Round 3 Petrosian vs Portisch, 1974  (E20) Nimzo-Indian, 22 moves, 1/2-1/2 Round 4 Portisch vs Petrosian, 1974  (D10) Queen's Gambit Declined Slav, 32 moves, 1/2-1/2 Round 5 Petrosian vs Portisch, 1974  (A30) English, Symmetrical, 35 moves, 1-0 Round 6 Portisch vs Petrosian, 1974 (C10) French, 35 moves, 1/2-1/2 Round 7 Petrosian vs Portisch, 1974  (D59) Queen's Gambit Declined, Tartakower, 13 moves, 1/2-1/2 Round 8 Portisch vs Petrosian, 1974  (B39) Sicilian, Accelerated Fianchetto, Breyer Variation, 29 moves, 1/2-1/2 Round 9 Petrosian vs Portisch, 1974  (A15) English, 27 moves, 1-0 Round 10 Portisch vs Petrosian, 1974  (D63) Queen's Gambit Declined, Orthodox Defense, 33 moves, 1-0 round 11 Petrosian vs Portisch, 1974  (A13) English, 19 moves, 1/2-1/2 Round 12 Portisch vs Petrosian, 1974  (D10) Queen's Gambit Declined Slav, 66 moves, 1-0 Round 13 Petrosian vs Portisch, 1974  (D30) Queen's Gambit Declined, 40 moves, 1-0 13 games