Withers, Mark
Current rating: 1438
| Grand Prix London 2013 (GTC limited) | starting rating: 1455 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 228 | Stroilov, Yuri (1500) | Won 2-0 | +181473 |
| 2sealed | 54 | Hernes, Robert (1519) | Won 2-0 | +191492 |
| 3sealed | 55 | Benard, Aurelien (1561) | Lost 0-2 | -161476 |
| 4sealed | 550 | Boroski, Derrick (1497) | Lost 1-2 | -181458 |
| 5sealed | 523 | Devis, Larry (1326) | Lost 1-2 | -201438 |
| top | average opponent: 1481record: 2-3 | new rating: 1438 | ||
| Grand Prix Manchester 2012 (DKA limited) | starting rating: 1447 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 82 | Van Straalen, Roeland (1581) | Lost 0-2 | -161431 |
| 2sealed | 181 | Platt, John (1481) | Won 2-0 | +191450 |
| 3sealed | 100 | Ziegelheim, Jan (1552) | Lost 0-2 | -161434 |
| 4sealed | 193 | Jones, Scott [ENG] (1481) | Won 2-0 | +191453 |
| 5sealed | 162 | Bamberger, Mark (1511) | Won 2-1 | +191472 |
| 6sealed | 135 | Cassidy, James (1519) | Lost 1-2 | -171455 |
| top | average opponent: 1521record: 3-3 | new rating: 1455 | ||
| Grand Prix London 2011 (MBS limited) | starting rating: 1500 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 231 | Helmersson, Petter (1507) | Lost 1-2 | -181482 |
| 2sealed | 324 | Inerot, Niclas (1513) | Lost 1-2 | -171465 |
| 3sealed | 342 | Trivedi, Deepam (1464) | Lost 0-2 | -181447 |
| top | average opponent: 1495record: 0-3 | new rating: 1447 | ||