USA: US Open - Doubles - Main |
| 1/32-finals | Hiraki R./Helgeson N. G. | Singer-Bath C./Vildova H. | 1:2 (6:4, 4:6, 4:6) | details | 02.09.1998 |
United Kingdom: Wimbledon - Doubles - Main |
| 1/8-finals | Grande R./Helgeson N. G. | Raymond L./Stubbs R. | 1:2 (7:5, 0:6, 3:6) | details | 27.06.1998 |
| 1/16-finals | Grande R./Helgeson N. G. | Kim E./Saeki M. | 2:0 (6:3, 6:3) | details | 26.06.1998 |
| 1/32-finals | Appelmans S./Oremans M. | Grande R./Helgeson N. G. | 1:2 (7:5, 1:6, 7:9) | details | 24.06.1998 |
United Kingdom: Wimbledon - Mixed Doubles - Main |
| 1/32-finals | MacPhie B./Davenport L. | Wheaton D./Helgeson N. G. | 2:0 (7:65, 6:4) | details | 24.06.1998 |
United Kingdom: Eastbourne - Doubles - Main |
| 1/8-finals | Grande R./Helgeson N. G. | Adams K./Bollegraf M. | 1:2 (6:4, 4:6, 2:6) | details | 15.06.1998 |
France: French Open - Mixed Doubles - Main |
| 1/8-finals | Lobo L./Williams S. | Grabb J./Helgeson N. G. | 2:1 (6:4, 3:6, 6:0) | details | 02.06.1998 |
| 1/16-finals | Knowles M./Kournikova A. | Grabb J./Helgeson N. G. | 1:2 (6:3, 4:6, 3:6) | details | 31.05.1998 |
France: French Open - Doubles - Main |
| 1/32-finals | Farina Elia S./Habsudova K. | Callens E./Helgeson N. G. | 2:0 (6:1, 6:1) | details | 29.05.1998 |
Japan: Tokyo 3 - Doubles - Main |
| Quarter-finals | Kijimuta N./Smith N. | De Beer S./Helgeson N. G. | 2:1 (7:5, 5:7, 7:6) | details | 16.04.1998 |
| 1/8-finals | De Beer S./Helgeson N. G. | Obata S./Shibata K. | 2:1 (6:3, 2:6, 7:6) | details | 13.04.1998 |
USA: Miami - Doubles - Main |
| 1/32-finals | Labat F./Park S. | Helgeson N. G./Lee J. | 2:1 (6:7, 6:3, 7:6) | details | 16.03.1998 |
USA: Indian Wells - Doubles - Main |
| 1/8-finals | Helgeson N. G./Lee J. | Kijimuta N./Smith N. | 0:2 (1:6, 2:6) | details | 11.03.1998 |
| 1/16-finals | Helgeson N. G./Lee J. | Hiraki R./Paz M. | 2:0 (6:3, 6:2) | details | 09.03.1998 |
USA: Oklahoma City - Doubles - Main |
| Quarter-finals | Golarsa L./Huber L. | De Villiers N./Helgeson N. G. | 2:0 (6:3, 7:5) | details | 25.02.1998 |
| 1/8-finals | Martincova E./Olsza A. | De Villiers N./Helgeson N. G. | 0:2 (6:7, 4:6) | details | 23.02.1998 |
Australia: Australian Open - Doubles - Main |
| 1/32-finals | Helgeson N. G./Krizan T. | Bollegraf M./Sanchez-Vicario A. | 1:2 (6:3, 3:6, 3:6) | details | 19.01.1998 |
Australia: Australian Open - Mixed Doubles - Main |
| 1/16-finals | Mirnyi M./Likhovtseva E. | Montana F./Helgeson N. G. | 2:0 (6:2, 6:4) | details | 19.01.1998 |
New Zealand: Auckland - Doubles - Main |
| Quarter-finals | De Villiers N./Jones D. | Callens E./Helgeson N. G. | 0:0 RET. (5:3) | details | 07.01.1998 |
| 1/8-finals | Hy-Boulais P./Jeyaseelan S. | Callens E./Helgeson N. G. | 0:2 (2:6, 2:6) | details | 05.01.1998 |
USA: US Open - Doubles - Main |
| 1/32-finals | Callens E./Helgeson N. G. | Savchenko-Neiland L./Sukova H. | 0:2 (3:6, 5:7) | details | 27.08.1997 |
United Kingdom: Wimbledon - Doubles - Main |
| Quarter-finals | Callens E./Helgeson N. G. | Savchenko-Neiland L./Sukova H. | 0:2 (4:6, 4:6) | details | 30.06.1997 |
| 1/8-finals | Callens E./Helgeson N. G. | Frazier A./Po K. | 2:0 (7:64, 6:3) | details | 28.06.1997 |
United Kingdom: Wimbledon - Mixed Doubles - Main |
| 1/16-finals | Nijssen T./Basuki Y. | Keil M./Helgeson N. G. | 2:0 (6:3, 6:4) | details | 26.06.1997 |
| 1/32-finals | Keil M./Helgeson N. G. | Kilderry P./Testud S. | 2:1 (4:6, 6:0, 6:3) | details | 24.06.1997 |
United Kingdom: Eastbourne - Doubles - Main |
| 1/8-finals | Helgeson N. G./Woodroffe L. | Arendt N./Bollegraf M. | 1:2 (6:7, 7:5, 2:6) | details | 16.06.1997 |
United Kingdom: Birmingham - Doubles - Main |
| 1/8-finals | Basuki Y./McNeil L. | Callens E./Helgeson N. G. | 2:0 (6:2, 6:2) | details | 11.06.1997 |
| 1/16-finals | De Lone E./Pratt N. | Callens E./Helgeson N. G. | 1:2 (6:4, 4:6, 1:6) | details | 09.06.1997 |