| date | stage | club1 | club2 | goals | |
| 1998-07-22 | Preliminary_Round | Celtic(Scotland) | St.Patricks_Athletic(Ireland) | 0 | 0 | - |
| 1998-07-22 | Preliminary_Round | FK_Obilic(Serbia) | IBV_Vestmannaeyjar(Iceland) | 2 | 0 | - |
| 1998-07-22 | Preliminary_Round | HJK_Helsinki(Finland) | FK_Yerevan(Armenia) | 2 | 0 | - |
| 1998-07-22 | Preliminary_Round | Liteks_Lovech(Bulgaria) | Halmstads_BK(Sweden) | 2 | 0 | - |
| 1998-07-22 | Preliminary_Round | Steaua_Bucuresti(Romania) | Flora_Tallinn(Estonia) | 4 | 1 | - |
| 1998-07-22 | Preliminary_Round | LKS_Lodz(Poland) | Kapaz_Ganja(Azerbaijan) | 4 | 1 | - |
| 1998-07-22 | Preliminary_Round | Kareda_Siauliai(Lithuania) | NK_Maribor(Slovenia) | 0 | 3 | - |
| 1998-07-22 | Preliminary_Round | Dinamo_Tbilisi(Georgia) | Vllaznia_Shkoder(Albania) | 3 | 0 | tech |
| 1998-07-22 | Preliminary_Round | Valletta_FC(Malta) | Anorthosis_Famagusta(Cyprus) | 0 | 2 | - |
| 1998-07-22 | Preliminary_Round | Zimbru_Chisinau(Moldova) | Ujpest_TE(Hungary) | 1 | 0 | - |
| 1998-07-22 | Preliminary_Round | Grasshoppers_Zurich(Switzerland) | Jeunesse_dEsch(Luxembourg) | 6 | 0 | - |
| 1998-07-22 | Preliminary_Round | Dynamo_Kiev(Ukraine) | Barry_Town(Wales) | 8 | 0 | - |
| 1998-07-22 | Preliminary_Round | Sileks_Kratovo(North_Macedonia) | Club_Brugge(Belgium) | 0 | 0 | - |
| 1998-07-22 | Preliminary_Round | Beitar_Jerusalem(Israel) | B36_Torshavn(Faroe Islands) | 4 | 1 | - |
| 1998-07-22 | Preliminary_Round | Cliftonville(Northern Ireland) | 1.FC_Kosice(Slovakia) | 1 | 5 | - |
| 1998-07-22 | Preliminary_Round | Skonto_Riga(Latvia) | Dinamo_Minsk(Belarus) | 0 | 0 | - |
| 1998-07-29 | Preliminary_Round | St.Patricks_Athletic(Ireland) | Celtic(Scotland) | 0 | 2 | - |
| 1998-07-29 | Preliminary_Round | IBV_Vestmannaeyjar(Iceland) | FK_Obilic(Serbia) | 1 | 2 | - |
| 1998-07-29 | Preliminary_Round | FK_Yerevan(Armenia) | HJK_Helsinki(Finland) | 0 | 3 | - |
| 1998-07-29 | Preliminary_Round | Halmstads_BK(Sweden) | Liteks_Lovech(Bulgaria) | 2 | 1 | - |
| 1998-07-29 | Preliminary_Round | Flora_Tallinn(Estonia) | Steaua_Bucuresti(Romania) | 3 | 1 | - |
| 1998-07-29 | Preliminary_Round | Kapaz_Ganja(Azerbaijan) | LKS_Lodz(Poland) | 1 | 3 | - |
| 1998-07-29 | Preliminary_Round | NK_Maribor(Slovenia) | Kareda_Siauliai(Lithuania) | 1 | 0 | - |
| 1998-07-29 | Preliminary_Round | Vllaznia_Shkoder(Albania) | Dinamo_Tbilisi(Georgia) | 3 | 1 | - |
| 1998-07-29 | Preliminary_Round | Anorthosis_Famagusta(Cyprus) | Valletta_FC(Malta) | 6 | 0 | - |
| 1998-07-29 | Preliminary_Round | Ujpest_TE(Hungary) | Zimbru_Chisinau(Moldova) | 3 | 1 | - |
| 1998-07-29 | Preliminary_Round | Jeunesse_dEsch(Luxembourg) | Grasshoppers_Zurich(Switzerland) | 0 | 2 | - |
| 1998-07-29 | Preliminary_Round | Barry_Town(Wales) | Dynamo_Kiev(Ukraine) | 1 | 2 | - |
| 1998-07-29 | Preliminary_Round | Club_Brugge(Belgium) | Sileks_Kratovo(North_Macedonia) | 2 | 1 | - |
| 1998-07-29 | Preliminary_Round | B36_Torshavn(Faroe Islands) | Beitar_Jerusalem(Israel) | 0 | 1 | - |
| 1998-07-29 | Preliminary_Round | 1.FC_Kosice(Slovakia) | Cliftonville(Northern Ireland) | 8 | 0 | - |
| 1998-07-29 | Preliminary_Round | Dinamo_Minsk(Belarus) | Skonto_Riga(Latvia) | 1 | 2 | - |
| 1998-08-12 | Qualifying_Round | Rosenborg_BK(Norway) | Club_Brugge(Belgium) | 2 | 0 | - |
| 1998-08-12 | Qualifying_Round | Manchester_United(England) | LKS_Lodz(Poland) | 2 | 0 | - |
| 1998-08-12 | Qualifying_Round | Liteks_Lovech(Bulgaria) | Spartak(Russia) | 0 | 5 | - |
| 1998-08-12 | Qualifying_Round | Galatasaray(Turkey) | Grasshoppers_Zurich(Switzerland) | 2 | 1 | - |
| 1998-08-12 | Qualifying_Round | Celtic(Scotland) | Dynamo_Zagreb(Croatia) | 1 | 0 | - |
| 1998-08-12 | Qualifying_Round | NK_Maribor(Slovenia) | PSV_Eindhoven(Netherlands) | 2 | 1 | - |
| 1998-08-12 | Qualifying_Round | Dynamo_Kiev(Ukraine) | Sparta_Praha(Czech Republic) | 0 | 1 | - |
| 1998-08-12 | Qualifying_Round | 1.FC_Kosice(Slovakia) | Brondby_IF(Denmark) | 0 | 2 | - |
| 1998-08-12 | Qualifying_Round | Internazionale(Italy) | Skonto_Riga(Latvia) | 4 | 0 | - |
| 1998-08-12 | Qualifying_Round | Olympiakos_Piraeus(Greece) | Anorthosis_Famagusta(Cyprus) | 2 | 1 | - |
| 1998-08-12 | Qualifying_Round | Benfica(Portugal) | Beitar_Jerusalem(Israel) | 6 | 0 | - |
| 1998-08-12 | Qualifying_Round | Dinamo_Tbilisi(Georgia) | Athletic_Bilbao(Spain) | 2 | 1 | - |
| 1998-08-12 | Qualifying_Round | HJK_Helsinki(Finland) | FC_Metz(France) | 1 | 0 | - |
| 1998-08-12 | Qualifying_Round | Bayern_Munchen(Germany) | FK_Obilic(Serbia) | 4 | 0 | - |
| 1998-08-12 | Qualifying_Round | Sturm_Graz(Austria) | Ujpest_TE(Hungary) | 4 | 0 | - |
| 1998-08-12 | Qualifying_Round | Steaua_Bucuresti(Romania) | Panathinaikos(Greece) | 2 | 2 | - |
| 1998-08-26 | Qualifying_Round | Club_Brugge(Belgium) | Rosenborg_BK(Norway) | 4 | 2 | - |
| 1998-08-26 | Qualifying_Round | LKS_Lodz(Poland) | Manchester_United(England) | 0 | 0 | - |
| 1998-08-26 | Qualifying_Round | Spartak(Russia) | Liteks_Lovech(Bulgaria) | 6 | 2 | - |
| 1998-08-26 | Qualifying_Round | Grasshoppers_Zurich(Switzerland) | Galatasaray(Turkey) | 2 | 3 | - |
| 1998-08-26 | Qualifying_Round | Dynamo_Zagreb(Croatia) | Celtic(Scotland) | 3 | 0 | - |
| 1998-08-26 | Qualifying_Round | PSV_Eindhoven(Netherlands) | NK_Maribor(Slovenia) | 4 | 1 | extra_time |
| 1998-08-26 | Qualifying_Round | Sparta_Praha(Czech Republic) | Dynamo_Kiev(Ukraine) | 0 | 1 | pen-1:3 |
| 1998-08-26 | Qualifying_Round | Brondby_IF(Denmark) | 1.FC_Kosice(Slovakia) | 0 | 1 | - |
| 1998-08-26 | Qualifying_Round | Skonto_Riga(Latvia) | Internazionale(Italy) | 1 | 3 | - |
| 1998-08-26 | Qualifying_Round | Anorthosis_Famagusta(Cyprus) | Olympiakos_Piraeus(Greece) | 2 | 4 | - |
| 1998-08-26 | Qualifying_Round | Beitar_Jerusalem(Israel) | Benfica(Portugal) | 4 | 2 | - |
| 1998-08-26 | Qualifying_Round | Athletic_Bilbao(Spain) | Dinamo_Tbilisi(Georgia) | 1 | 0 | - |
| 1998-08-26 | Qualifying_Round | FC_Metz(France) | HJK_Helsinki(Finland) | 1 | 1 | - |
| 1998-08-26 | Qualifying_Round | FK_Obilic(Serbia) | Bayern_Munchen(Germany) | 1 | 1 | - |
| 1998-08-26 | Qualifying_Round | Ujpest_TE(Hungary) | Sturm_Graz(Austria) | 2 | 3 | - |
| 1998-08-26 | Qualifying_Round | Panathinaikos(Greece) | Steaua_Bucuresti(Romania) | 6 | 3 | - |
| 1998-09-16 | Group_A(1) | FC_Porto(Portugal) | Olympiakos_Piraeus(Greece) | 2 | 2 | - |
| 1998-09-16 | Group_A(1) | Dynamo_Zagreb(Croatia) | Ajax(Netherlands) | 0 | 0 | - |
| 1998-09-30 | Group_A(1) | Ajax(Netherlands) | FC_Porto(Portugal) | 2 | 1 | - |
| 1998-09-30 | Group_A(1) | Olympiakos_Piraeus(Greece) | Dynamo_Zagreb(Croatia) | 2 | 0 | - |
| 1998-10-21 | Group_A(1) | FC_Porto(Portugal) | Dynamo_Zagreb(Croatia) | 3 | 0 | - |
| 1998-10-21 | Group_A(1) | Olympiakos_Piraeus(Greece) | Ajax(Netherlands) | 1 | 0 | - |
| 1998-11-25 | Group_A(1) | Olympiakos_Piraeus(Greece) | FC_Porto(Portugal) | 2 | 1 | - |
| 1998-11-25 | Group_A(1) | Ajax(Netherlands) | Dynamo_Zagreb(Croatia) | 0 | 1 | - |