| Mar 18, 2025 | Muhammed | 1–0 | Amarathunga | Round 9: Muhammed, Shuaau - Amarathunga, Kosala Sandeepa Chamikara | French Defense: Tarrasch Variation | |
| Sep 22, 2024 | Kulpruethanon | 1–0 | Amarathunga | 45th FIDE Chess Olympiad | Catalan Opening: Open Defense | |
| Sep 21, 2024 | Amarathunga | 1–0 | Saif | 45th FIDE Chess Olympiad | Zukertort Opening: Nimzo-Larsen Variation | |
| Sep 20, 2024 | Ondozi | 1–0 | Amarathunga | 45th FIDE Chess Olympiad | Queen's Gambit Declined: Exchange Variation, Sämisch Variation | |
| Sep 19, 2024 | Amarathunga | ½–½ | Ahmed Hassan | 45th FIDE Chess Olympiad | Zukertort Opening: Sicilian Invitation | |
| Sep 18, 2024 | Lesbros | 0–1 | Amarathunga | 45th FIDE Chess Olympiad | English Opening: Agincourt Defense, Catalan Defense Accepted | |
| Sep 16, 2024 | Amarathunga | 0–1 | Song | 45th FIDE Chess Olympiad | Sicilian Defense: French Variation, Westerinen Attack | |
| Sep 15, 2024 | Amarathunga | ½–½ | Delgado Rosas | 45th FIDE Chess Olympiad | Nimzo-Larsen Attack: Classical Variation | |
| Sep 14, 2024 | Nguyen | 1–0 | Amarathunga | 45th FIDE Chess Olympiad | Nimzo-Indian Defense: Normal Variation, Ragozin Variation | |
| Sep 13, 2024 | Silva | 1–0 | Amarathunga | 45th FIDE Chess Olympiad | French Defense: Chigorin Variation | |
| Sep 12, 2024 | Amarathunga | 1–0 | Bongo Akanga Ndjila | 45th FIDE Chess Olympiad | Nimzo-Larsen Attack: Classical Variation | |
| Sep 11, 2024 | Quesada Perez | 1–0 | Amarathunga | 45th FIDE Chess Olympiad | Queen's Gambit Declined: Three Knights Variation | |
| Aug 2, 2024 | Amarathunga | 0–1 | Barsov | Round 8: Amarathunga, Kosala Sandeepa Chamikara - Barsov, Alexei | French Defense: Exchange Variation | |
| Aug 1, 2024 | Deepan Chakkravarthy J. | 1–0 | Amarathunga | Round 6: Deepan Chakkravarthy J. - Amarathunga, Kosala Sandeepa Chamikara | French Defense: Exchange Variation | |
| Jul 31, 2024 | Amarathunga | ½–½ | Samaranayake | Round 5: Amarathunga, Kosala Sandeepa Chamikara - Samaranayake, Pamok Methdinu | Sicilian Defense: Nyezhmetdinov-Rossolimo Attack, Fianchetto Variation | |
| Nov 21, 2021 | Amarathunga | 0–1 | Kazi Afsan Rawnak | Asian Academies Hybrid Chess Championship | Sicilian Defense: Moscow Variation, Main Line | |
| Nov 21, 2021 | Amarathunga | 0–1 | Sakline Mostafa | Asian Academies Hybrid Chess Championship | Sicilian Defense: Four Knights Variation | |
| Nov 21, 2021 | Amarathunga | 0–1 | Babaei | Asian Academies Hybrid Chess Championship | Caro-Kann Defense: Classical Variation | |
| Nov 21, 2021 | waleed Abdullah | ½–½ | Amarathunga | Asian Academies Hybrid Chess Championship | French Defense: Winawer Variation, Poisoned Pawn Variation, Main Line | |
| Nov 21, 2021 | Naimanov | ½–½ | Amarathunga | Asian Academies Hybrid Chess Championship | French Defense: King's Indian Attack | |
| Nov 21, 2021 | Mohammadi | 1–0 | Amarathunga | Asian Academies Hybrid Chess Championship | King's Pawn Game | |
| Nov 3, 2021 | Tin | 1–0 | Amarathunga | Asian Club Hybrid Chess Championships 2021 - Default | Queen's Gambit Declined: Ragozin Defense | |
| Nov 3, 2021 | Akrami | 0–1 | Amarathunga | Asian Club Hybrid Chess Championships 2021 - Default | Indian Defense: Seirawan Attack | |
| Nov 3, 2021 | Hossain | 1–0 | Amarathunga | Asian Club Hybrid Chess Championships 2021 - Default | King's Pawn Game | |
| Aug 16, 2021 | Amarathunga | 0–1 | Choudhury | World Youth Cup 2021 O16-G12 - Open 16 | Sicilian Defense: Delayed Alapin Variation, with e6 | |
| Aug 16, 2021 | Amarathunga | 1–0 | Li | World Youth Cup 2021 O16-G12 - Open 16 | Caro-Kann Defense: Tartakower Variation | |
| Aug 16, 2021 | Amarathunga | 0–1 | Ozsac | World Youth Cup 2021 O16-G12 - Open 16 | Sicilian Defense: Nyezhmetdinov-Rossolimo Attack | |
| Aug 16, 2021 | Amarathunga | 0–1 | Centrih | World Youth Cup 2021 O16-G12 - Open 16 | Italian Game: Two Knights Defense, Traxler Counterattack, Knight Sacrifice Line | |
| Aug 16, 2021 | Ong | 0–1 | Amarathunga | World Youth Cup 2021 O16-G12 - Open 16 | Queen's Gambit Declined: Ragozin Defense | |
| Aug 16, 2021 | Sukhbat | 1–0 | Amarathunga | World Youth Cup 2021 O16-G12 - Open 16 | French Defense: Advance Variation, Main Line | |
| Aug 16, 2021 | Jingjang | 0–1 | Amarathunga | World Youth Cup 2021 O16-G12 - Open 16 | Indian Defense: London System | |
| Aug 16, 2021 | Tsephe | 1–0 | Amarathunga | World Youth Cup 2021 O16-G12 - Open 16 | Zukertort Opening | |
| Aug 16, 2021 | Walsh | 0–1 | Amarathunga | World Youth Cup 2021 O16-G12 - Open 16 | Nimzo-Indian Defense: Sämisch Variation | |
