de Groof, Stein
Current rating: 1529
Record: 19-19
| Grand Prix Stockholm 2016 (EMN limited) | starting rating: 1550 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 365 | Moller, Gunnar (1605) | Lost 0-2 | -171533 |
| 2sealed | 346 | Borger, Bryan (1497) | Won 2-1 | +171550 |
| 3sealed | 473 | Rossmark, Bart (1566) | Won 2-0 | +181568 |
| 4sealed | 146 | Sondergaard, Andreas (1526) | Lost 0-2 | -191549 |
| 5sealed | 278 | Sanzen, Bengt (1395) | Lost 1-2 | -201529 |
| top | average opponent: 1518record: 2-3 | new rating: 1529 | ||
| Grand Prix Utrecht 2015 (MM2 limited) | starting rating: 1570 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 1353 | van Zwol, Koen (1463) | Lost 1-2 | -201550 |
| top | record: 0-1 | new rating: 1550 | ||
| Grand Prix Warsaw 2014 (JOU limited) | starting rating: 1498 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 211 | Domagalski, Tomasz (1470) | Won 2-1 | +181516 |
| 2sealed | 85 | Szafranski, Krzysztof (1520) | Won 2-1 | +181534 |
| 3sealed | 124 | Delvigne, Emmanuel (1576) | Won 2-0 | +181552 |
| 4sealed | 108 | Flis, Grzegorz (1704) | Won 2-0 | +211573 |
| 5sealed | 31 | Mayer, Manuel (1664) | Lost 1-2 | -161557 |
| 6sealed | 58 | Prinzell, Johan (1727) | Won 2-1 | +211578 |
| 7sealed | 77 | Rausch, Oliver (1774) | Lost 0-0 | -151563 |
| 8sealed | 63 | Saito, Tomoharu (1753) | Lost 0-2 | -141549 |
| 9sealed | 119 | Ton, Jonathan (1701) | Won 2-0 | +211570 |
| top | average opponent: 1654record: 6-3 | new rating: 1570 | ||
| Grand Prix Gothenburg 2013 (DGM limited) | starting rating: 1516 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 238 | Nicosia, Alvaro (1539) | Lost 1-2 | -181498 |
| top | record: 0-1 | new rating: 1498 | ||
| Grand Prix Lisbon 2012 (RTR limited) | starting rating: 1515 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 514 | Guillet, Jean-Philippe (1633) | Lost 0-2 | -161499 |
| 2sealed | 753 | Felix, Carolina (1482) | Won 2-0 | +181517 |
| 3sealed | 691 | Gonzalez, Jairo (1481) | Won 2-0 | +171534 |
| 4sealed | 612 | Daniel, Santos (1519) | Lost 0-2 | -181516 |
| top | average opponent: 1529record: 2-2 | new rating: 1516 | ||
| Grand Prix Prague 2011 (NPH limited) | starting rating: 1528 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 517 | Della Pietra, Carlos Alberto (1500) | Won 2-1 | +181546 |
| 2sealed | 501 | Reymond, Pascal (1702) | Lost 1-2 | -161530 |
| 3sealed | 668 | Siebert, Hannes (1506) | Won 2-0 | +181548 |
| 4sealed | 602 | Tyssens, Geert (1600) | Lost 0-2 | -171531 |
| 5sealed | 662 | Hagan, Jonathan (1631) | Lost 0-2 | -161515 |
| top | average opponent: 1588record: 2-3 | new rating: 1515 | ||
| Grand Prix Paris 2011 (MBS limited) | starting rating: 1530 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 671 | Tait, Heather (1500) | Won 2-0 | +181548 |
| 2sealed | 542 | Karafotis, Konstantinos (1401) | Won 2-0 | +151563 |
| 3sealed | 583 | Koska, Adam (1815) | Won 2-0 | +231586 |
| 4sealed | 535 | Kazanskis, Viktors (1467) | Lost 1-2 | -201566 |
| 5sealed | 648 | Zayas, Haimir (1498) | Lost 0-2 | -201546 |
| 6sealed | 672 | Cuffini, Reynald (1532) | Lost 0-2 | -181528 |
| top | average opponent: 1535record: 3-3 | new rating: 1528 | ||
| Grand Prix Bochum 2010 (SOM limited) | starting rating: 1500 | |||
| round | table | opponent (rating) | result | Δrating |
| 1sealed | 44 | Schultz-Nielsen, Martin (1525) | Won 2-0 | +181518 |
| 2sealed | 87 | Ast, Haiko (1515) | Won 2-0 | +181536 |
| 3sealed | 60 | Zeeb, Martin (1544) | Won 2-1 | +191555 |
| 4sealed | 76 | Ruel, Antoine (1689) | Lost 0-2 | -161539 |
| 5sealed | 79 | Darras, Alexandre (1781) | Won 2-0 | +221561 |
| 6sealed | 111 | Krause, Jens (1869) | Lost 0-2 | -121549 |
| 7sealed | 82 | Kuebler, Dennis (1529) | Lost 0-2 | -191530 |
| top | average opponent: 1636record: 4-3 | new rating: 1530 | ||