BERLIN (AP) -- Germany's center-left Social Democrats on Sunday elected a combative new leader to spearhead their recovery from a disastrous election result while guiding them through a fractious coalition government with Chancellor Angela Merkel's conservatives.
Andrea Nahles, who heads the party's parliamentary group, won two-thirds of delegates' votes at a congress in Wiesbaden. She defeated Simone Lange, the left-leaning mayor of the northern town of Flensburg, to become the party's first female leader.
The Social Democrats slumped to their worst result since World War II in September's election, securing only 20.5 percent of the vote. It was their fourth consecutive defeat.
They initially vowed to go into opposition, but reluctantly changed course after Merkel's negotiations with two smaller parties collapsed and eventually agreed to enter another "grand coalition" as the chancellor's junior partners.
The decision to enter the new government was a bruising and divisive one sealed by a ballot of party members earlier this year. Martin Schulz, Merkel's luckless challenger in the election, stepped down as party leader in February after less than a year in charge.
It is unusual in Germany for prospective party leaders to face a challenge, and Lange's long-shot candidacy reflected simmering divisions.
Lange told delegates Sunday that she was "your alternative for real renewal" and asked: "Are we serious about it, or will we make do with nice words?"
The 47-year-old Nahles, who joined the Social Democrats 30 years ago, has held several senior party posts and served as Merkel's labor minister for four years until last fall.
A longtime left-winger who has evolved into a pragmatic centrist, she now faces the task — along with Vice Chancellor Olaf Scholz, the new finance minister — of turning the party's fortunes around. Recent polls have shown its support running slightly below its showing at the election.
"A party can be renewed in government. I want to start proving that tomorrow," Nahles said. "But our six ministers cannot do good work if we don't support them as well. They must be able to rely on this party."
She called on Germans to "stand with us against right-wing populism and chauvinism," an allusion to the nationalist Alternative for Germany party. And she urged her party to look forward as it reviews its platform, rather than to past fights over welfare-state reforms.
"I'm not new," she acknowledged. But "I know this party."