Underhill, Simon
Current rating: 1506
Record: 13-14-1
| Grand Prix Atlanta 2018 (modern) | starting rating: 1526 | |||
| round | table | opponent (rating) | result | Δrating |
| 2modern | 255 | Whipple, Joseph (1493) | Lost 0-2 | -191507 |
| 3modern | 603 | Morgan, Dustin (1496) | Won 2-1 | +181525 |
| 4modern | 451 | Corwin, Andrew (1431) | Lost 0-2 | -201505 |
| 5modern | 490 | DeCoeur, David (1535) | Won 2-0 | +191524 |
| 6modern | 413 | Swan, Alan (1522) | Lost 1-2 | -181506 |
| top | average opponent: 1495record: 2-3 | new rating: 1506 | ||
| Grand Prix Orlando 2018 (M19 standard) | starting rating: 1573 | |||
| round | table | opponent (rating) | result | Δrating |
| 2standard | 9 | Dedrick, John (1919) | Lost 1-2 | -121561 |
| 3standard | 272 | Yarbrough, Christopher (1644) | Lost 1-2 | -161545 |
| 4standard | 424 | Scianni, John (1482) | Lost 1-2 | -191526 |
| top | average opponent: 1682record: 0-3 | new rating: 1526 | ||
| Grand Prix Atlanta 2017 (XLN standard) | starting rating: 1488 | |||
| round | table | opponent (rating) | result | Δrating |
| 1standard | 162 | Maxim, Christopher (1502) | Won 2-0 | +181506 |
| 2standard | 111 | Simpson, Drew (1518) | Won 2-0 | +191525 |
| 3standard | 129 | Ayers, William (1543) | Lost 0-2 | -181507 |
| 4standard | 379 | Swenson, Luke (1644) | Won 2-0 | +201527 |
| 5standard | 276 | Savoy, Allen (1466) | Draw 1-1 | -11526 |
| 6standard | 201 | Zhang, Songbai (1816) | Lost 1-2 | -131513 |
| 7standard | 309 | Schell, Alan (1521) | Won 2-1 | +191532 |
| 8standard | 209 | Orellana, Manuel (1803) | Won 2-0 | +221554 |
| 9standard | 140 | Lerch, Corey (1573) | Won 2-1 | +191573 |
| 10standard | 86 | Gooch, Spencer (1540) | Lost 0-2 | -191554 |
| 11standard | 143 | Nguyen, Minh (1647) | Lost 0-2 | -161538 |
| 12standard | 159 | Hill, Jeff (1537) | Won 2-0 | +181556 |
| 13standard | 124 | Wrixon, Raymond (1535) | Lost 1-2 | -191537 |
| 14standard | 134 | Mahon, Chance (1512) | Won 2-0 | +181555 |
| 15standard | 111 | Bardier, Daniel (1583) | Won 2-0 | +181573 |
| top | average opponent: 1583record: 9-5-1 | new rating: 1573 | ||
| Grand Prix Orlando 2017 (AER limited) | starting rating: 1500 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 705 | Mizell, Ryan (1500) | Lost 1-2 | -181482 |
| 2sealed | 848 | Bess, Ken (1482) | Lost 0-2 | -181464 |
| 3sealed | 1104 | Cooper, Larry (1463) | Won 2-0 | +181482 |
| 4sealed | 1062 | Shrake, Christopher (1556) | Won 2-0 | +191501 |
| 5sealed | 1010 | Medrano, Adonnys (1768) | Lost 1-2 | -131488 |
| top | average opponent: 1554record: 2-3 | new rating: 1488 | ||