| Game |
| Result | Moves |
Year | Event/Locale | Opening |
| 26. Semyon Lomasov vs D Vocaturo |
| 0-1 | 36 | 2017 | European Individual Chess Championship | C80 Ruy Lopez, Open |
| 27. Semyon Lomasov vs Alexej Nikonov |
| 1-0 | 35 | 2017 | Chigorin Memorial | B52 Sicilian, Canal-Sokolsky (Rossolimo) Attack |
| 28. Yurii Marinskii vs Semyon Lomasov |
| ½-½ | 36 | 2017 | Chigorin Memorial | C68 Ruy Lopez, Exchange |
| 29. Semyon Lomasov vs N Klepikov |
| 1-0 | 43 | 2017 | Chigorin Memorial | B78 Sicilian, Dragon, Yugoslav Attack, 10.castle long |
| 30. Evgenij Lesovoi vs Semyon Lomasov |
| 0-1 | 27 | 2017 | Chigorin Memorial | D32 Queen's Gambit Declined, Tarrasch |
| 31. Semyon Lomasov vs D Paravyan |
| ½-½ | 40 | 2017 | Chigorin Memorial | C47 Four Knights |
| 32. M Litvinov vs Semyon Lomasov |
| 0-1 | 51 | 2017 | Chigorin Memorial | B13 Caro-Kann, Exchange |
| 33. Semyon Lomasov vs K Alekseenko |
| 0-1 | 38 | 2017 | Chigorin Memorial | B69 Sicilian, Richter-Rauzer Attack, 7...a6 Defense, 11.Bxf6 |
| 34. S Swaminathan vs Semyon Lomasov |
| ½-½ | 49 | 2017 | Chigorin Memorial | A59 Benko Gambit |
| 35. Semyon Lomasov vs S Vokhidov |
| 1-0 | 44 | 2017 | Chigorin Memorial | E06 Catalan, Closed, 5.Nf3 |
| 36. Dorian Micottis vs Semyon Lomasov |
| 0-1 | 43 | 2017 | World Junior Championship | C11 French |
| 37. Semyon Lomasov vs Yuanhe Zhao |
| 1-0 | 63 | 2017 | World Junior Championship | C03 French, Tarrasch |
| 38. Semyon Lomasov vs M Karthikeyan |
| ½-½ | 34 | 2017 | World Junior Championship | C45 Scotch Game |
| 39. S L Narayanan vs Semyon Lomasov |
| ½-½ | 75 | 2017 | World Junior Championship | E17 Queen's Indian |
| 40. Semyon Lomasov vs O Kobo |
| 1-0 | 71 | 2017 | World Junior Championship | C11 French |
| 41. G Oparin vs Semyon Lomasov |
| ½-½ | 38 | 2017 | World Junior Championship | E11 Bogo-Indian Defense |
| 42. Semyon Lomasov vs H Martirosyan |
| 1-0 | 44 | 2017 | World Junior Championship | B12 Caro-Kann Defense |
| 43. Tran Tuan Minh vs Semyon Lomasov |
| ½-½ | 31 | 2017 | World Junior Championship | E11 Bogo-Indian Defense |
| 44. Semyon Lomasov vs M Petrosyan |
| ½-½ | 24 | 2017 | World Junior Championship | C52 Evans Gambit |
| 45. R Praggnanandhaa vs Semyon Lomasov |
 | ½-½ | 60 | 2017 | World Junior Championship | A06 Reti Opening |
| 46. Semyon Lomasov vs Yan Liu |
| ½-½ | 33 | 2017 | World Junior Championship | A45 Queen's Pawn Game |
| 47. A Korobov vs Semyon Lomasov |
| 1-0 | 44 | 2018 | Aeroflot Open | E17 Queen's Indian |
| 48. Semyon Lomasov vs V Shinkevich |
| 1-0 | 44 | 2018 | Aeroflot Open | E70 King's Indian |
| 49. G Sargissian vs Semyon Lomasov |
| ½-½ | 65 | 2018 | Aeroflot Open | A46 Queen's Pawn Game |
| 50. Semyon Lomasov vs A Predke |
| 0-1 | 46 | 2018 | Aeroflot Open | E00 Queen's Pawn Game |
Kibitzing
