| Singles | |
|---|---|
| 1998 Croatia Open Umag | |
| Champion |  Bohdan Ulihrach [1] |
| Runner-up |  Magnus Norman |
| Score | 6–3, 7–6(7–0) |
| Draw | 32 (4 Q / 3 WC ) |
| Seeds | 8 |
The 1998 Croatia Open Umag was a tennis tournament played on outdoor clay courts in Umag, Croatia that was part of the International Series of the 1998 ATP Tour. The tournament was held from July 27 through August 2, 1998.
Champion seeds are indicated in bold text while text in italics indicates the round in which those seeds were eliminated.
Carlos Moyá (first round) Félix Mantilla (quarterfinals)
Karol Kučera (quarterfinals)
Gustavo Kuerten (quarterfinals) Dominik Hrbatý (first round) Magnus Norman (final) Bohdan Ulihrach (champion)
Davide Sanguinetti (second round)| Semifinals | Final [1] | ||||||||||||
 Juan Antonio Marín | 63 | 3 | |||||||||||
| 6 | Magnus Norman | 7 | 6 | ||||||||||
| 6 | Magnus Norman | 3 | 60 | ||||||||||
| 7 | Bohdan Ulihrach | 6 | 7 | ||||||||||
 Mariano Puerta | 3 | 3 | |||||||||||
| 7 | Bohdan Ulihrach | 6 | 6 | ||||||||||
| First round | Second round | Quarterfinals | Semifinals | ||||||||||||||||||||||||
| 1 | C Moyá | 5 | 6 | 1 | |||||||||||||||||||||||
 P Haarhuis | 7 | 4 | 6 | P Haarhuis | w/o | ||||||||||||||||||||||
 J Knippschild | 3 | 1 | J Burillo | ||||||||||||||||||||||||
| J Burillo | 6 | 6 | P Haarhuis | 2 | 62 | ||||||||||||||||||||||
| JA Marín | 4 | 6 | 6 | JA Marín | 6 | 7 | |||||||||||||||||||||
| R Furlan | 6 | 3 | 4 | JA Marín | 7 | 3 | 6 | ||||||||||||||||||||
 O Stanoytchev | 4 | 6 | 4 | 8 | D Sanguinetti | '64 | 6 | 3 | |||||||||||||||||||
| 8 | D Sanguinetti | 6 | 3 | 6 | JA Marín | 63 | 3 | ||||||||||||||||||||
| 3 | K Kučera | 6 | 6 | 6 | M Norman | 7 | 6 | ||||||||||||||||||||
| S Bruguera | 4 | 0 | 3 | K Kučera | 7 | 6 | |||||||||||||||||||||
| Q |  B Urh | 6 | 6 | B Urh | 5 | 2 | |||||||||||||||||||||
| Q | L Němeček | 3 | 1 | 3 | K Kučera | 6 | 4 | 4 | |||||||||||||||||||
| Q | S Cobolli | 5 | 6 | 6 | 6 | M Norman | 1 | 6 | 6 | ||||||||||||||||||
| Q | T Čatár | 7 | 4 | 3 | S Cobolli | 65 | 6 | 2 | |||||||||||||||||||
| WC |  I Ljubičić | 64 | 6 | 3 | 6 | M Norman | 7 | 3 | 6 | ||||||||||||||||||
| 6/WC | M Norman | 7 | 4 | 6 | |||||||||||||||||||||||
| First round | Second round | Quarterfinals | Semifinals | ||||||||||||||||||||||||
| 5 | D Hrbatý | 3 | 6 | 4 | |||||||||||||||||||||||
| M Puerta | 6 | 2 | 6 | M Puerta | 6 | 4 | 6 | ||||||||||||||||||||
| M Martelli | 4 | 4 | J Sánchez | 4 | 6 | 4 | |||||||||||||||||||||
| J Sánchez | 6 | 6 | M Puerta | 6 | 1 | 7 | |||||||||||||||||||||
| J Novák | 6 | 1 | 6 | 4 | G Kuerten | 4 | 6 | 65 | |||||||||||||||||||
| V Santopadre | 2 | 6 | 1 | J Novák | 6 | 61 | 3 | ||||||||||||||||||||
| M-K Goellner | 0 | 63 | 4 | G Kuerten | 4 | 7 | 6 | ||||||||||||||||||||
| 4 | G Kuerten | 6 | 7 | M Puerta | 3 | 3 | |||||||||||||||||||||
| 7 | B Ulihrach | 7 | 6 | 7 | B Ulihrach | 6 | 6 | ||||||||||||||||||||
 D Pescariu | 65 | 4 | 7 | B Ulihrach | 7 | 3 | 6 | ||||||||||||||||||||
| J Díaz | 6 | 6 | J Díaz | 68 | 6 | 4 | |||||||||||||||||||||
| WC | E Rasberger | 3 | 3 | 7 | B Ulihrach | 6 | 3 | 7 | |||||||||||||||||||
| M Carlsson | 6 | 5 | 3 | 2 | F Mantilla | 3 | 6 | 62 | |||||||||||||||||||
| A Voinea | 1 | 7 | 6 | A Voinea | 3 | 0 | |||||||||||||||||||||
| L Burgsmüller | 3 | 3 | 2 | F Mantilla | 6 | 6 | |||||||||||||||||||||
| 2 | F Mantilla | 6 | 6 | ||||||||||||||||||||||||
The 1998 Sydney International was a tennis tournament played on outdoor hard courts at the NSW Tennis Centre in Sydney, Australia that was part of the International Series of the 1998 ATP Tour and of Tier II of the 1998 WTA Tour. The tournament was held from 11 through 17 January 1998.
The 1998 Croatian Indoors was a men's tennis tournament played on indoor carpet courts in Split, Croatia, that was part of the International Series of the 1998 ATP Tour. It was the only edition of the tournament and was held 2–9 February 1998.
The 1998 Guardian Direct Cup was a men's tennis tournament played on indoor carpet courts in London, Great Britain, that was part of the International Series Gold of the 1998 ATP Tour. It was the 21st edition of the tournament and was held 23 February – 1 March.
The 1998 Copenhagen Open was a men's tennis tournament played on indoor carpet courts in Copenhagen, Denmark that was part of the International Series of the 1998 ATP Tour. It was the eleventh edition of the tournament and was held from 9 March through 15 March 1998.
The 1998 Salem Open was a men's tennis tournament played on Hard courts in Hong Kong that was part of the International Series of the 1998 ATP Tour. It was the 23rd edition of the tournament and was held from 6–12 April 1998.
The 1998 Japan Open Tennis Championships was a tennis tournament played on outdoor hard courts at the Ariake Coliseum in Tokyo in Japan that was part of the International Series Gold of the 1998 ATP Tour and of Tier III of the 1998 WTA Tour. The tournament was held from April 13 through April 19, 1998.
The 1998 International Raiffeisen Grand Prix was a men's tennis tournament played on Clay in St. Pölten, Austria that was part of the International Series of the 1998 ATP Tour. It was the eighteenth edition of the tournament and was held from 18–24 May 1998.
The 1998 Internazionali di Carisbo was a men's tennis tournament played on Clay in Bologna, Italy that was part of the International Series of the 1998 ATP Tour. It was the fourteenth edition of the tournament and was held from 8–14 June 1998.
The 1998 Rado Open was a men's tennis tournament played on Clay in Gstaad, Switzerland that was part of the International Series of the 1998 ATP Tour. It was the thirty-first edition of the tournament and was held from 6 July – 12 July 1998.
The 1998 Hall of Fame Tennis Championships was a tennis tournament played on grass courts at the International Tennis Hall of Fame in Newport, Rhode Island in the United States and was part of the World Series of the 1998 ATP Tour. It was the 23rd edition of the tournament and was held from July 6 through July 12, 1998.
The 1998 Hall of Fame Tennis Championships was a tennis tournament played on grass courts at the International Tennis Hall of Fame in Newport, Rhode Island in the United States and was part of the World Series of the 1998 ATP Tour. It was the 23rd edition of the tournament and was held from July 6 through July 12, 1998.
The 1998 Swedish Open was a men's tennis tournament played on Clay in Båstad, Sweden that was part of the International Series of the 1998 ATP Tour. It was the fifty-first edition of the tournament and was held from 6–12 July 1998.
The 1998 Mercedes Cup was a men's tennis tournament played on clay courts in Stuttgart, Germany, that was part of the International Series Gold of the 1998 ATP Tour. It was the fiftieth edition of the tournament and was held 20 July – 26 July.
The 1998 Mercedes Cup was a men's tennis tournament played on Clay in Stuttgart, Germany, that was part of the International Series Gold of the 1998 ATP Tour. It was the fiftieth edition of the tournament and was held 20 July – 26 July.
The 1998 Legg Mason Tennis Classic was a men's tennis tournament played on outdoor hard courts in Washington, D.C., United States, that was part of the International Series Gold of the 1998 ATP Tour. It was the twenty-ninth edition of the tournament and was held 20 July – 26 July.
The 1998 Croatia Open Umag was a tennis tournament played on outdoor clay courts in Umag, Croatia that was part of the International Series of the 1998 ATP Tour. The tournament was held from July 27 through August 2, 1998.
The 1998 Generali Open was a men's tennis tournament played on Clay in Kitzbühel, Austria that was part of the International Series of the 1998 ATP Tour. It was the forty-third edition of the tournament and was held from 27 July – 2 August 1998.
The 1998 Generali Open was a men's tennis tournament played on Clay in Kitzbühel, Austria that was part of the International Series of the 1998 ATP Tour. It was the forty-third edition of the tournament and was held from 27 July – 2 August 1998.
The 1999 Croatian Indoors was a men's tennis tournament played on carpet courts in Copenhagen, Denmark, that was part of the International Series of the 1999 ATP Tour. It was the twelfth edition of the tournament and was held from 2 February until 9 February 1998.
The 2007 Croatia Open Umag was the 18th occurrence of the Croatia Open Umag tennis tournament, held on July 23–29.