2025 Southern California Open
32 players participated in this 6-round tournament, held from 29 Aug 2025 to 01 Sept 2025 in Glendale, CA, United States. 17 titled players from 7 federations. Top 10 Elo average was 2452, and top seed was Tigran L. Petrosian (🇦🇲 ARM, GM, 2551).
Viktor Matviishen (🇺🇦 UKR, GM, 2516) won with 5.5/6, ahead of Sebastian Lukas Kostolansky (5.0) and Oleksii Bilych (4.5). Matviishen won solo starting round 5.
The biggest upset came in round 4: Ridhi Varma Danduprolu (WCM, 1827) beat Reynaldo Del Pilar (2077), a +250-point gap.
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How it unfolded
Top 6 · 6 roundsGM Viktor Matviishen led from R3; +0.5-point edge over the runner-up.
GM Viktor Matviishen held the sole lead from R3 through R6 without losing it.
GM Viktor Matviishen beat IM Sebastian Lukas Kostolansky (Black).
GM Viktor Matviishen 3 wins (R1–R3)IM Sebastian Lukas Kostolansky 4 wins (R3–R6)
Key matchups · top 4
Head-to-head between the four finishers| Player | 1 | 2 | 3 | 4 |
|---|---|---|---|---|
| 1GMViktor Matviishen | * | 1 | 1 | — |
| 2IMSebastian Lukas Kostolansky | 0 | * | — | — |
| 3IMOleksii Bilych | 0 | — | * | — |
| 4Nathaniel Philip Moor | — | — | — | * |
Grille américaine
| # | Player | Elo | Fed | R1 | R2 | R3 | R4 | R5 | R6 | Pts | Bu C1 | Bu | SB | Perf | Δ |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Matviishen, ViktorGM | 2516 | UKR | +32B | +2N | +7B | =26N | +3B | +4N | 5.5 | 18.0 | 18.0 | 17.50 | 2825 | +18.9 |
| 2 | Kostolansky, Sebastian LukasIM | 2434 | SVK | +15N | −1B | +14N | +13B | +18N | +5B | 5.0 | 17.0 | 19.0 | 13.50 | 2515 | +7.7 |
| 3 | Bilych, OleksiiIM | 2433 | UKR | +22B | +4N | =26B | +7N | −1N | +30B | 4.5 | 15.5 | 16.5 | 10.50 | 2556 | +11.5 |
| 4 | Corrales Jimenez, FidelGM | 2535 | USA | +19N | −3B | +15N | +8B | +11N | −1B | 4.0 | 19.0 | 21.0 | 11.00 | 2431 | -5.4 |
| 5 | Mikaelyan, ArmanGM | 2492 | ARM | =13N | +31B | +10N | =11B | +26B | −2N | 4.0 | 15.0 | 15.5 | 7.75 | 2442 | -1.7 |
| 6 | Moor, Nathaniel Philip | 2206 | USA | +28B | −7N | +23B | −30N | +13B | +11B | 4.0 | 11.5 | 12.5 | 8.00 | 2263 | +10.2 |
| 7 | Bilovil, BogdanIM | 2477 | UKR | +8N | +6B | −1N | −3B | =12N | +16B | 3.5 | 20.5 | 23.0 | 11.50 | 2328 | -9.4 |
| 8 | Gasparyan, David | 2194 | USA | −7B | +22N | +28B | −4N | +20B | =9N | 3.5 | 14.5 | 15.5 | 6.25 | 2206 | +8.8 |
| 9 | Rostomyan, MikayelFM | 2274 | ARM | =17N | −13B | =31N | +15B | +14N | =8B | 3.5 | 13.5 | 14.0 | 8.25 | 2090 | -24.8 |
| 10 | Guo, EthanFM | 2311 | USA | =24N | +17B | −5B | +29N | =16N | =25B | 3.5 | 12.0 | 13.0 | 6.25 | 2205 | -11.4 |
| 11 | Pyrih, RomanIM | 2425 | UKR | =14B | +27N | +29B | =5N | −4B | −6N | 3.0 | 15.5 | 16.5 | 5.25 | 2228 | -12.7 |
| 12 | Golsefidy, Sepehr | 2112 | USA | F | F | =17N | +27B | =7B | +23N | 3.0 | 8.5 | 8.5 | 5.50 | 2274 | +30.0 |
| 13 | Chinni, RishabhCM | 2063 | USA | =5B | +9N | =18B | −2N | −6N | =14B | 2.5 | 19.0 | 21.0 | 7.75 | 2230 | +42.4 |
| 14 | Zhu, Alexander | 2063 | USA | =11N | =16B | −2B | +28N | −9B | =13N | 2.5 | 16.5 | 17.5 | 5.00 | 2144 | +17.2 |
| 15 | Bagdasarian, Ararat | 1934 | USA | −2B | +32N | −4B | −9N | =22N | +24B | 2.5 | 15.5 | 15.5 | 2.25 | 2088 | +35.6 |
| 16 | Zhou, Ruoyu | 2163 | USA | F | =14N | +20B | =18N | =10B | −7N | 2.5 | 13.5 | 13.5 | 6.00 | 2192 | +8.0 |
| 17 | Karthikeyan, Harishkumar | 1927 | USA | =9B | −10N | =12B | −19B | =27N | +32N | 2.5 | 13.0 | 13.0 | 3.75 | 2080 | +40.0 |
| 18 | Virtanen, TeemuFM | 2284 | FIN | F | F | =13N | =16B | −2B | +21N | 2.0 | 12.0 | 12.0 | 4.50 | 2223 | -6.2 |
| 19 | Casella, MichaelFM | 2079 | USA | −4B | −28N | +22B | +17N | F | F | 2.0 | 9.0 | 9.0 | 4.00 | 2046 | -5.4 |
| 20 | Danduprolu, Ridhi VarmaWCM | 1827 | USA | F | F | −16N | +32B | −8N | +27B | 2.0 | 7.0 | 7.0 | 1.00 | 2101 | +51.2 |
| 21 | Carreto Nieto, GiovanniCM | 2233 | MEX | F | F | =27B | =23N | +29B | −18B | 2.0 | 5.5 | 5.5 | 2.25 | 2062 | -16.6 |
| 22 | Gartland, James | 1932 | USA | −3N | −8B | −19N | F | =15B | +29N | 1.5 | 13.5 | 13.5 | 2.25 | 1968 | +2.0 |
| 23 | Xia, Joshua | 1949 | USA | F | F | −6N | =21B | +24N | −12B | 1.5 | 10.5 | 10.5 | 2.50 | 2030 | +13.6 |
| 24 | Ragavan, Samarth Rajesh | 1917 | USA | =10B | −29N | +32B | −25N | −23B | −15N | 1.5 | 10.0 | 10.0 | 1.75 | 1913 | -8.8 |
| 25 | Abrahamyan, TatevIM | 2343 | USA | F | F | F | +24B | F | =10N | 1.5 | 5.0 | 5.0 | 3.25 | 2320 | +0.4 |
| 26 | Petrosian, Tigran L.GM | 2551 | ARM | F | F | =3N | =1B | −5N | F | 1.0 | 14.0 | 14.0 | 5.00 | 2355 | -7.9 |
| 27 | Liang, Ethan Y | 1970 | USA | F | −11B | =21N | −12N | =17B | −20N | 1.0 | 12.5 | 12.5 | 2.25 | 1854 | -32.8 |
| 28 | Chidipudi, Kishan | 1846 | USA | −6N | +19B | −8N | −14B | F | F | 1.0 | 12.0 | 12.0 | 2.00 | 1943 | +14.4 |
| 29 | Zhou, Ivan | 2045 | USA | F | +24B | −11N | −10B | −21N | −22B | 1.0 | 11.5 | 11.5 | 1.50 | 1924 | -34.4 |
| 30 | Joel Paul GantaCM | 2067 | IND | F | F | F | +6B | F | −3N | 1.0 | 8.5 | 8.5 | 4.00 | 2320 | +11.8 |
| 31 | Bhatta, Rohit | 2016 | USA | F | −5N | =9B | F | F | F | 0.5 | 7.5 | 7.5 | 1.75 | 2152 | +4.8 |
| 32 | Del Pilar, Reynaldo | 2077 | USA | −1N | −15B | −24N | −20N | F | −17B | 0.0 | 14.0 | 14.0 | 0.00 | 1216 | -59.8 |
Key insights
Biggest movers and upsets — the story behind the numbers.
- 1Danduprolu, Ridhi VarmaWCMUSA+51.22.0 pts · #21
- 2Chinni, RishabhCMUSA+42.42.5 pts · #17
- 3Karthikeyan, HarishkumarUSA+40.02.5 pts · #15
- 1Del Pilar, ReynaldoUSA-59.80.0 pts · #32
- 2Zhou, IvanUSA-34.41.0 pts · #29
- 3Liang, Ethan YUSA-32.81.0 pts · #28
- R4+250 Elo gap
- R2+233 Elo gap
- R6+219 Elo gap