Marek, Petr
Current rating: 1465
Record: 4-6
| Grand Prix Prague 2003 (LGN limited) | starting rating: 1463 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 71 | Buchtik, Roman (1500) | Won 2-0 | +191482 |
| 2sealed | 194 | Hulle, Tomas (1518) | Lost 1-2 | -171465 |
| 3sealed | 171 | Danek, Jiri (1464) | Won 2-1 | +181483 |
| 4sealed | 157 | Deinert, Sascha (1521) | Lost 0-2 | -181465 |
| 5sealed | 306 | Zoubal, Frantisek (1468) | Won 2-0 | +181483 |
| 6sealed | 146 | van Bemmel, Simon (1481) | Lost 0-2 | -181465 |
| average opponent: 1492record: 3-3 | new rating: 1465 | |||
| Grand Prix Vienna 1999 (extended) | starting rating: 1500 | |||
| round | table | opponent (rating) | result | Δrating |
| 1extended | 13 | Facchetti, Eugenio (1500) | Lost 0-0 | -181482 |
| 2extended | 151 | Svedberg, Kim (1482) | Won 0-0 | +181500 |
| 3extended | 131 | Miklos, Tihor (1464) | Lost 0-0 | -191481 |
| 4extended | 126 | Baronio, Diego (1481) | Lost 0-0 | -181463 |
| average opponent: 1482record: 1-3 | new rating: 1463 | |||