Wins
423
Indexed tournament wins
Player record
Sean O'Neill
Losses
134
Indexed tournament losses
Matches
557
Decisive results
Win rate
75.9%
Across indexed matches
Peak rating
2,667
Highest rating in the available history.
Biggest upset
Mark Hazinski
2001 Nashville Open · May 13, 2001 · +137 rating
Open →Biggest loss
Lyashchuk, Rostyslav
2004 N. American Teams Open TT · Nov 28, 2004 · -474 rating
Open →Most frequent opponent
Yinghua Cheng
14 matches
Open →Rating trajectory
Published rating movement across recorded events.
Tournament history
79 tournament appearances · synced Aug 11, 2026, 4:11 AM
| Date | Tournament | Rating in | Rating after | Points changed | Record |
|---|---|---|---|---|---|
| Apr 16, 1995 | Potomac Spring OpenTournament · View matches | 2,610 | 2,597 | -13+2 / -15 | 4W / 2L |
| Feb 22, 1995 | US Men's Team TrialsTournament · View matches | 2,617 | 2,610 | -7+10 / -17 | 2W / 3L |
| Dec 18, 1994 | US NationalsTournament · View matches | 2,579 | 2,617 | +38 | 9W / 1L |
| Nov 27, 1994 | US TeamsTournament · View matches | 2,613 | 2,579 | -34 | 8W / 3L |
| Oct 30, 1994 | 1994 Southern OpenTournament · View matches | 2,605 | 2,613 | +8+9 / -1 | 5W / 1L |
| Oct 28, 1994 | Pan-Am TrialsTournament · View matches | 2,618 | 2,605 | -13+10 / -23 | 6W / 2L |
| Oct 9, 1994 | NTTC October OpenTournament · View matches | 2,625 | 2,618 | -7+0 / -7 | 1W / 1L |
| Oct 2, 1994 | Maryland CircuitTournament · View matches | 2,619 | 2,625 | +6+7 / -1 | 4W / 1L |
| Sep 4, 1994 | NTTC September OpenTournament · View matches | 2,618 | 2,619 | +1+8 / -7 | 3W / 1L |
| Aug 21, 1994 | Sun TV OpenTournament · View matches | 2,624 | 2,618 | -6+9 / -15 | 5W / 2L |
| Aug 6, 1994 | Seafair Pacific NW ChampionshiTournament · View matches | 2,624 | 2,624 | 0+0 / 0 | 3W / 0L |
| Jul 10, 1994 | Olympic FestivalTournament · View matches | 2,644 | 2,624 | -20 | 7W / 2L |
| Jul 4, 1994 | US OpenTournament · View matches | 2,646 | 2,644 | -2+7 / -9 | 3W / 2L |
| Jun 19, 1994 | NTTC June OpenTournament · View matches | 2,654 | 2,646 | -8+0 / -8 | 2W / 1L |
| May 22, 1994 | NTTC May OpenTournament · View matches | 2,665 | 2,654 | -11+2 / -13 | 2W / 1L |
| May 1, 1994 | Hall of FameTournament · View matches | 2,667 | 2,665 | -2 | 5W / 2L |
| Apr 17, 1994 | NTTC April OpenTournament · View matches | 2,663 | 2,667 | +4+6 / -2 | 1W / 1L |
| Mar 20, 1994 | NTTC March OpenTournament · View matches | 2,649 | 2,663 | +14+14 / 0 | 2W / 0L |
| Feb 27, 1994 | NTTC February OpenTournament · View matches | 2,648 | 2,649 | +1+3 / -2 | 1W / 1L |
61–79 of 79
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