The third candidate, Health Minister Jens Spahn, was eliminated in the first round of voting earlier on Friday.

The CDU’s secretary general, Kramp-Karrenbauer made her case ahead of the vote by saying the CDU had to maintain its position as the “last unicorn in Europe,” the bloc’s last successful catch-all party.

She also rejected claims that she was the “mini Merkel”.

“People consider me a ‘mini,’ a copy, a simple ‘more of the same,’ but I can tell you that I stand here as my own person, just as life has shaped me and of that I am proud,” she told delegates attending he conference.

The 56-year-old former state premier gained the nickname because of her pragmatic centrist political style and her reputation as a Merkel loyalist.

Merz, a former CDU heavyweight who has repeatedly vowed to win back voters from the far-right Alternative for Germany (AfD) party, said the fact that the AfD is Germany’s largest opposition party is “simply unbearable” and has to change.

“It threatens not only our ability to form a parliamentary majority, but also the very stability of our country,” he said. “We need a strategy change in relation to our competitors and in terms of the communication with people in our country.”

The AfD dismissed Kramp-Karrenbauer’s election as a continuation of the Merkel years.

“Kramp-Karrenbauer means: More of the same. It’s Merkel 2.0,” AfD parliamentary leader Alice Weidel said Friday.

One of Kramp-Karrenbauer’s early tests is likely to help stabilise the CDU’s fragile coalition with the crisis-hit centre-left Social Democrats (SPD).

However, SPD leader Andrea Nahles quickly offered Kramp-Karrenbauer the opportunity to work closely together and to continue the CDU-SPD coalition government in Berlin with the Christian Social Union (CSU), the CDU’s Bavarian sister party.

“Now it is time to solve problems: securing the future of pensions, recognising the value of work, strengthening cohesion in Europe,” Nahles said.

The run-off vote between Kramp-Karrenbauer and Merz came shortly after Merkel received a standing ovation that lasted nearly 10 minutes in response to her final speech as CDU chief.

Dozens of CDU delegates at the conference in Hamburg held up banners reading “Danke Chefin” – German for “Thanks, boss” – as they listened to Merkel’s final words after 18 years at the helm of the party.

Merkel cited Germany’s balanced budget policy, the end of military conscription in 2011 and the management of the refugee crisis in 2015-16 as major achievements of the conservative CDU during her tenure as leader.

“We have a lot left to do,” Merkel said.

Speaking shortly before the conference, Merkel said she hoped the CDU would emerge from the vote “primed, motivated and united.”

“Together we want our CDU, as a strong party of the centre, to live up to its mandate, to radiate persuasive power and to provide the right offering for the future of our country,” Merkel said.

Merkel intends to serve out the end of her term until then, but Friday’s vote may also be decisive on whether she lasts that long.

According to a poll released by public broadcaster ARD on Thursday, the majority of Germans say that Merkel should remain in office for the full three years, while slightly more than a third said Merkel should stand down early.

Kramp-Karrenbauer was elected CDU secretary general in February as part of efforts to give the party fresh momentum. She served as premier of the small southwestern German state of Saarland from 2011 to 2018.

In addition to sections of business, the 63-year-old Merz had won support from conservative CDU members including party veteran Wolfgang Schaeuble. Many had seen him as pushing the party to the right, thereby standing up to the challenge represented by the AfD.