The group stage of the 1998–99 UEFA Champions League began on 16 September 1998 and ended on 9 December 1998. Eight teams qualified automatically for the group stage, while 16 more qualified via a preliminary round. The 24 teams were divided into six groups of four, and the teams in each group played against each other on a home-and-away basis, meaning that each team played a total of six group matches. For each win, teams were awarded three points, with one point awarded for each draw.
Seeding
Seeding was based on the UEFA associations 1998 ranking,[1] similarly to the previous season.[2] Title holders and champions of nations ranked 1–5 were put in the Pot 1. Champions of nations ranked 6–7 as well as runners-up of nations ranked 1–5 (except France) formed Pot 2. The remaining qualified runners-up (from the nations 6–8) and champions of top three nations ranked below 7 formed Pot 3. Finally, the remaining six national champions formed Pot 4.
Key to colours in group tables
Group winners and best-ranked runners-up advance to the knockout stage
^CET (UTC+1) for matches from 4 November 1998, and CEST (UTC+2) for matches to 21 October 1998.
^Originally scheduled for 25 November, delayed for political tensions between Turkey and Italy due to the Öcalan affair.[10][11][12][13]
^Real Madrid were ordered to play one match away from their usual home ground due to crowd trouble at their last home game in UEFA competition against Borussia Dortmund in the first leg of the 1997–98 Champions League semi-final.[14]
^"Porto v Olympiacos, 16 September 1998" (JSON). Union of European Football Associations. Retrieved 20 March 2022.
^"Croatia Zagreb v Ajax, 16 September 1998" (JSON). Union of European Football Associations. Retrieved 20 March 2022.
^"Olympiacos v Ajax, 21 October 1998" (JSON). Union of European Football Associations. Retrieved 20 March 2022.
^"Croatia Zagreb v Porto, 4 November 1998" (JSON). Union of European Football Associations. Retrieved 20 March 2022.
^"Ajax v Croatia Zagreb, 25 November 1998" (JSON). Union of European Football Associations. Retrieved 20 March 2022.
^"Athletic Bilbao v Rosenborg, 16 September 1998" (JSON). Union of European Football Associations. Retrieved 20 March 2022.
^"Galatasaray v Rosenborg, 4 November 1998" (JSON). Union of European Football Associations. Retrieved 20 March 2022.
^Ullman, Seva (1998-12-02). "Ocalan violence feared at soccer match". The Independent. Retrieved 2023-12-04.
^Delaney, Sarah (1998-11-25). "ITALY SEEKS HELP ON TURKISH CLASH". Washington Post. Retrieved 2023-12-04.
^Metcalf, Rupert (1998-11-25). "Football: Around The World - Juventus spared journey to Turkey". The Independent. Retrieved 2023-12-04.
^Morris, Chris (1998-12-03). "Troops on alert for grudge match". The Guardian. Retrieved 2023-12-04.
^Fylan, Kevin (1998-04-05). "Football: Real punished for trouble at European Cup tie". The Independent. Retrieved 2023-12-04.
^"Real Madrid v Sturm Graz, 21 October 1998" (JSON). Union of European Football Associations. Retrieved 20 March 2022.
^"Spartak Moscow v Internazionale, 25 November 1998" (JSON). Union of European Football Associations. Retrieved 20 March 2022.
^"Spartak Moscow v Sturm Graz, 25 November 1998" (JSON). Union of European Football Associations. Retrieved 20 March 2022.
^"Bayern Munich v Manchester United, 30 September 1998" (JSON). Union of European Football Associations. Retrieved 20 March 2022.
^"Barcelona v Brøndby, 30 September 1998" (JSON). Union of European Football Associations. Retrieved 20 March 2022.
^"Barcelona v Bayern Munich, 4 November 1998" (JSON). Union of European Football Associations. Retrieved 20 March 2022.
^Kyryliuk, Viktor (31 January 2014). "Валерий Лобановский. Четыре жизни в футболе. Жизнь четвертая. 1997-13 мая 2002. Классик - часть 6" (in Russian). Tribuna. Retrieved 23 May 2019.
^"Dynamo Kyiv v Lens, 30 September 1998" (JSON). Union of European Football Associations. Retrieved 20 March 2022.
^"Dynamo Kyiv v Panathinaikos, 25 November 1998" (JSON). Union of European Football Associations. Retrieved 20 March 2022.
^"Benfica v Kaiserslautern, 25 November 1998" (JSON). Union of European Football Associations. Retrieved 20 March 2022.
^"Kaiserslautern v HJK, 9 December 1998" (JSON). Union of European Football Associations. Retrieved 20 March 2022.
Note: In 1991–92, the competition was still known as the European Cup, but is included as it was the first to use a group stage format. In that season and 1992–93, there was no knockout phase between the group stage and final.