Prehn, Jon
Current rating: 1534
Record: 15-14-2
| Grand Prix Birmingham 2017 (modern) | starting rating: 1542 | |||
| round | table | opponent (rating) | result | Δrating |
| 3modern | 105 | Longoria, Daniel (1617) | Lost 1-2 | -171525 |
| 4modern | 210 | Beattie, David (1540) | Won 2-0 | +191544 |
| 5modern | 244 | Manteca, Federico (1560) | Lost 0-2 | -181526 |
| 6modern | 385 | [anonymous] | Won 2-1 | +181544 |
| 7modern | 175 | Alexander, Jon (1553) | Won 2-1 | +191563 |
| 8modern | 120 | Freitas, Rui (1586) | Won 2-0 | +181581 |
| 9modern | 138 | Lechado Artigues, Pedro (1845) | Won 2-1 | +231604 |
| 10modern | 40 | Ekstrom, Markus (1563) | Won 2-0 | +171621 |
| 11modern | 33 | Deane, Peter (1634) | Lost 0-2 | -181603 |
| 12modern | 115 | Garcia Guerrero, Luis (1701) | Lost 1-2 | -161587 |
| 13modern | 155 | Ward, Peter (1734) | Lost 1-2 | -151572 |
| 14modern | 137 | Frith, Louis (1526) | Lost 1-2 | -191553 |
| 15modern | 162 | Enberg, Mikael (1512) | Lost 0-2 | -191534 |
| top | average opponent: 1610record: 6-7 | new rating: 1534 | ||
| Grand Prix Copenhagen 2017 (modern) | starting rating: 1555 | |||
| round | table | opponent (rating) | result | Δrating |
| 3modern | 98 | Horosiewicz, Lukas (1658) | Won 2-1 | +201575 |
| 4modern | 47 | Watson, Alex (1544) | Lost 1-2 | -191556 |
| 5modern | 242 | Szwebs, Michal (1652) | Lost 0-2 | -161540 |
| 6modern | 390 | Hansen, Tim (1583) | Won 2-1 | +191559 |
| 7modern | 256 | Schwank, Johannes (1513) | Won 2-1 | +171576 |
| 8modern | 231 | Bardh, Simon (1702) | Lost 1-2 | -161560 |
| 9modern | 264 | Sorensen, Jeppe7840 (1546) | Lost 0-2 | -181542 |
| top | average opponent: 1600record: 3-4 | new rating: 1542 | ||
| Grand Prix Prague 2017 (AER limited) | starting rating: 1556 | |||
| round | table | opponent (rating) | result | Δrating |
| 2sealed | 253 | Janak, Josef (1532) | Lost 0-2 | -181538 |
| 3sealed | 493 | Rieke, Konstantin (1502) | Won 2-0 | +171555 |
| top | average opponent: 1517record: 1-1 | new rating: 1555 | ||
| Grand Prix Brussels 2015 (BFZ standard) | starting rating: 1500 | |||
| round | table | opponent (rating) | result | Δrating |
| 1standard | 299 | Henry, Dimitri (1367) | Won 0-0 | +161516 |
| 2standard | 244 | Eriksson, Hampus (1536) | Lost 0-0 | -181498 |
| 3standard | 586 | Degrave, Geoffrey (1438) | Won 2-0 | +171515 |
| 4standard | 560 | Adel, E. (1522) | Won 2-1 | +181533 |
| 5standard | 371 | Colding-Jorgensen, Martin (1653) | Won 2-0 | +201553 |
| 6standard | 163 | Keuning, Pieter (1620) | Draw 1-1 | +11554 |
| 7standard | 177 | Cools, Siegfried (1551) | Lost 0-2 | -181536 |
| 8standard | 282 | Gameiro, Kevin-Romain (1629) | Draw 1-1 | +21538 |
| 9standard | 303 | Ruegg, Pascal (1532) | Won 1-0 | +181556 |
| top | average opponent: 1539record: 5-2-2 | new rating: 1556 | ||