| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 26. G Mastrokoukos vs T Polak |
| 0-1 | 46 | 1990 | European Junior Championship 1990/91 | B22 Sicilian, Alapin |
| 27. T Werther vs G Mastrokoukos |
| 0-1 | 28 | 1990 | European Junior Championship 1990/91 | A57 Benko Gambit |
| 28. G Mastrokoukos vs Hracek |
| 0-1 | 39 | 1990 | European Junior Championship 1990/91 | B52 Sicilian, Canal-Sokolsky (Rossolimo) Attack |
| 29. G Van der Stricht vs G Mastrokoukos |
| 0-1 | 56 | 1990 | European Junior Championship 1990/91 | A57 Benko Gambit |
| 30. G Mastrokoukos vs R Djurhuus |
| 0-1 | 37 | 1990 | European Junior Championship 1990/91 | C00 French Defense |
| 31. K Ruxton vs G Mastrokoukos |
| ½-½ | 39 | 1990 | European Junior Championship 1990/91 | A04 Reti Opening |
| 32. G Mastrokoukos vs R Tuominen |
| 1-0 | 51 | 1990 | European Junior Championship 1990/91 | C02 French, Advance |
| 33. G Mastrokoukos vs A Olcayoz |
| ½-½ | 82 | 1990 | European Junior Championship 1990/91 | B22 Sicilian, Alapin |
| 34. G Mastrokoukos vs Blatny |
| 0-1 | 33 | 1991 | Corfu op | C50 Giuoco Piano |
| 35. Nunn vs G Mastrokoukos |
| 1-0 | 40 | 1991 | Kavala op | B33 Sicilian |
| 36. G Mastrokoukos vs P Velikov |
| ½-½ | 48 | 1991 | Kavala op | A06 Reti Opening |
| 37. G Mastrokoukos vs T Tsiolakidis |
| 1-0 | 33 | 1991 | Kavala op | A05 Reti Opening |
| 38. G Mastrokoukos vs K Nikolaidis |
| 1-0 | 46 | 1991 | Kavala op | A06 Reti Opening |
| 39. R Klovsky vs G Mastrokoukos |
| 0-1 | 37 | 1991 | Kavala op | B45 Sicilian, Taimanov |
| 40. G Mastrokoukos vs I Efimov |
| 0-1 | 51 | 1991 | Corfu op | A07 King's Indian Attack |
| 41. G Mastrokoukos vs R Bloemendaal |
| 1-0 | 60 | 1991 | Corfu op | E00 Queen's Pawn Game |
| 42. G Mastrokoukos vs E Grivas |
| ½-½ | 16 | 1991 | Kavala op | E67 King's Indian, Fianchetto |
| 43. H Konstandinidis vs G Mastrokoukos |
| 0-1 | 20 | 1991 | Chania Open | A46 Queen's Pawn Game |
| 44. G Mastrokoukos vs T Tsorbatzoglou |
| 1-0 | 28 | 1991 | Chania Open | B08 Pirc, Classical |
| 45. G Mastrokoukos vs A Kofidis |
| 1-0 | 43 | 1991 | Chania Open | A49 King's Indian, Fianchetto without c4 |
| 46. N Tripodakis vs G Mastrokoukos |
| 0-1 | 38 | 1991 | Chania Open | A56 Benoni Defense |
| 47. G Mastrokoukos vs I Rogers |
| ½-½ | 45 | 1991 | Chania Open | B30 Sicilian |
| 48. A Wojtkiewicz vs G Mastrokoukos |
| 1-0 | 26 | 1991 | Corfu op | D76 Neo-Grunfeld, 6.cd Nxd5, 7.O-O Nb6 |
| 49. Kotronias vs G Mastrokoukos |
 | 1-0 | 35 | 1991 | Chania Open | B33 Sicilian |
| 50. J Sinowjew vs G Mastrokoukos |
| 0-1 | 34 | 1991 | European Junior Championship 1990/91 | B45 Sicilian, Taimanov |
Kibitzing
