Berlin Mayor Kai Wegner on Friday abandoned his bid for re-election in September amid a long-running scandal involving a tennis match.

Wegner, from the conservative Christian Democrats (CDU), has governed the German capital in coalition with the centre-left Social Democrats (SPD) since 2023, but his poll ratings have suffered since a controversial incident earlier this year.

The mayor was forced to admit he played tennis on January 3 as an arson attack left 100,000 residents of the city without electricity during a cold spell, with the blackout lasting several days in some neighbourhoods.

The incident left many residents, opposition parties and his coalition partners furious, but Wegner apologized for his handling of the matter and was selected by party members as the CDU lead candidate for the election on September 20 with 93% of the vote.

Nevertheless, the scandal has rumbled on and returned to the headlines this week when a report in the Tagesspiegel newspaper on Tuesday alleged that Wegner lied about holding phone calls related to the power cut on the morning of the incident.

The centre-right CDU – the party of Chancellor Friedrich Merz – were convincing winners in the 2023 Berlin special election with 28.2% of the vote, but Wegner has haemorrhaged support since the turn of the year.

The latest Infratest dimap poll from July 1 showed the party in fourth place on just 17%, prompting CDU members to sound the alarm and move against Wegner.

The 53-year-old said he would remain in office as mayor until a new coalition is formed following the election on September 20.

Local CDU leaders later on Friday agreed to nominate Berlin Finance Senator Stefan Evers as the party’s new candidate for mayor, replacing Wegner, although the decision still requires formal approval from the party’s state executive. The 46-year-old has served as Berlin’s finance senator since 2023 and has also overseen the city’s culture portfolio since earlier this year.

The race remains extremely tight, with The Left – the successor to the Socialist Unity Party that ruled East Germany – leading the way on 20%, one year after it surprisingly finished top in Berlin during the national parliamentary election.

The Greens are on 19% and the far-right Alternative for Germany (AfD) on 18%, with the SPD further back on 13%.