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 |
|---|---|---|---|---|---|
| Nov 26, 2000 | No. Amer. Teams Open ChampionshipsTournament · View matches | 2,511 | 2,485 | -26 | 9W / 4L |
| Nov 19, 2000 | Potomac Millennium OpenTournament · View matches | 2,544 | 2,511 | -33 | 2W / 2L |
| Oct 8, 2000 | MDTTC October OpenTournament · View matches | 2,543 | 2,544 | +1+1 / 0 | 5W / 0L |
| Jun 10, 2000 | BumperNets June OpenTournament · View matches | 2,551 | 2,541 | -10+0 / -10 | 6W / 1L |
| Dec 21, 1997 | US NationalsTournament · View matches | 2,562 | 2,551 | -11+2 / -13 | 2W / 1L |
| Dec 7, 1997 | 1997 2nd Annual US Nationals "Tournament · View matches | 2,559 | 2,562 | +3+13 / -10 | 6W / 1L |
| Nov 30, 1997 | US Open Teams ChampionshipsTournament · View matches | 2,557 | 2,559 | +2+2 / 0 | 24W / 0L |
| Oct 5, 1996 | 3rd Ann. 1996 Oded Amitz-Lev MTournament · View matches | 2,556 | 2,557 | +1 | 4W / 1L |
| Feb 23, 1996 | 1996 US Olympic TrialsTournament · View matches | 2,569 | 2,556 | -13 | 7W / 6L |
| Feb 11, 1996 | 1996 Atlanta Cup TT ChallengeTournament · View matches | 2,575 | 2,569 | -6+0 / -6 | 1W / 1L |
| Jan 21, 1996 | NJTTC January OpenTournament · View matches | 2,577 | 2,575 | -2+0 / -2 | 4W / 1L |
| Dec 18, 1995 | USATT National ChampionshipsTournament · View matches | 2,569 | 2,577 | +8 | 3W / 1L |
| Nov 26, 1995 | US Open Team ChampionshipsTournament · View matches | 2,563 | 2,556 | -7 | 8W / 3L |
| Nov 19, 1995 | Potomac Fall OpenTournament · View matches | 2,544 | 2,563 | +19+25 / -6 | 3W / 1L |
| Oct 29, 1995 | NTTC October OpenTournament · View matches | 2,550 | 2,544 | -6+0 / -6 | 0W / 1L |
| Oct 1, 1995 | NTTC September OpenTournament · View matches | 2,550 | 2,550 | 0+4 / -4 | 1W / 1L |
| Jul 30, 1995 | 1995 Olympic FestivalTournament · View matches | 2,560 | 2,550 | -10 | 7W / 4L |
| Jul 16, 1995 | $8000 Detroit OpenTournament · View matches | 2,570 | 2,560 | -10+2 / -12 | 2W / 2L |
| Jun 18, 1995 | NTTC June OpenTournament · View matches | 2,575 | 2,570 | -5+1 / -6 | 1W / 1L |
| Jun 4, 1995 | Hall of FameTournament · View matches | 2,597 | 2,575 | -22+9 / -31 | 8W / 2L |