All the same, Merkel, a physicist, was fighting back tears when she gave a final speech as party leader, drawing a almost 10 minute standing ovation.
In her closing speech Friday, Chancellor Merkel singled out Kramp-Karrenbauer's success in the Saarland elections in 2017 which largely bucked the trend of heavy losses for the party in various other regional elections, largely due to the dramatic rise in support for the populist Alternative for Germany (AfD).
Annegret Kramp-Karrenbauer waves to delegates after receiving the most votes to become the next leader of Germany's Christian Democratic Union (CDU).
The two main candidates, CDU general secretary Annegret Kramp-Karrenbauer, known as AKK, and corporate lawyer Friedrich Merz are locked in a battle over whether to embrace or break with the veteran chancellor's legacy.
While she has often been dubbed "mini Merkel" for her steady, pragmatic style, she subtly distanced herself from the chancellor in the run-up to today's high-stakes vote.
The newly elected CDU head has previously opposed the idea of withdrawing support from the Nord Stream 2 project entirely, but suggested reducing the amount of gas obtained via the route from Russian Federation as a response to the recent Kerch incident involving Ukrainian naval ships. At 38, he would stand for a change of generation.
The protegee's win will come as a relief to Merkel, whose chances of staying on as chancellor until 2021 partly hinge on how well she gets on with the new CDU chair.
Health Minister Jens Spahn, another Merkel critic, is considered the outsider. She moved her party relentlessly to the centre, dropping military conscription, accelerating Germany's exit from nuclear energy, introducing benefits encouraging fathers to look after their young children and allowing the introduction of gay marriage.
This week, Merz - who has insisted in the face of widespread scepticism that he could work well with Merkel - won the backing of powerful former finance minister Wolfgang Schaeuble, now the parliamentary speaker. "And this is the motivation with which I am here and why I run for CDU party leadership", Spahn said.
After a smattering of applause throughout the course of her final speech as CDU chief, Merkel was bid farewell with a rousing standing ovation that lasted about 10 minutes and included a brief encore.
For years, Merkel's popularity lifted the CDU and its Bavaria-only sister party, the Christian Social Union.
"There's a desire for more inclusion and self-confidence in the party", she has said. He won 157 votes.
"There's a place for both in this party", Kramp-Karrenbauer said, adding the renewed confidence their party elections raised in Germans "must continue and must be connected with the goal that unites us all, to preserve and shape our great people's party".
"We are facing a turning point and need a breakthrough for the next years". "I have always wanted to do my government and party jobs with dignity, and one day to leave them with dignity. now it is time to open a new chapter". CDU delegates at the congress in Hamburg also held up signs saying "Thanks boss".