German Chancellor Angela Merkel has appeared with her main rival in a TV debate, two weeks ahead of an election, BBC reported.
Mrs Merkel and Frank Walter Steinmeier, the Foreign Minister, discussed nuclear power, executive pay and the idea of a minimum wage.
The two leaders have been in a coalition for the past four years.
Mrs Merkel wants her conservative CDU party to jettison Mr Steinmeier's centre-left SPD as a partner, in favour of the liberal Free Democrats (FDP).
Opinion polls suggest the CDU is on course to win enough votes for Mrs Merkel to stay on as chancellor.
Correspondents say few major areas of disagreement emerged during the 90-minute debate.
Neither of the candidates for chancellor is known for being particularly charismatic or telegenic, correspondents say.
Watched by a TV audience expected to number 20 million, the leaders discussed Afghanistan, the global financial crisis and nuclear power.
Mrs Merkel benefits from being the chancellor right now.
She is best placed to take the credit for everything that has gone right recently for Germany, like the country exiting recession, and General Motors agreeing to sell Opel to the Canadian car parts supplier Magna - the very deal the German government had been seeking.
Mrs Merkel said she could return the country to prior prosperity if she changed coalition partner.
"We can continue decisively on this path but preferably with a new government," she said.
On nuclear policy, the two leaders differed.
Former Chancellor Gerhard Schroeder decided to mothball Germany's nuclear reactors by about 2020, but Mrs Merkel said the question remained about whether nuclear energy would be needed for longer.
"It is, in my view, extremely important that we change to renewable energy and efficient energy as soon as possible... but all renewable energies are subsidised... and therefore I say [nuclear energy] would be a bridging technology but only until viable renewable energies really allow this changeover."
She was criticised by Mr Steinmeier, who said: "It is not responsible, and it is politically wrong to go back down the road of nuclear energy - because that is what we are really talking about here."
He warned that if nuclear energy was extended, then investment in renewable energy would end.
Opinion polls suggest the Social Democratic Party is at least 12% behind Mrs Merkel's centre-right bloc.
Immediately after the debate - named The TV Duel - surveys suggested there was no clear winner.
Broadcaster ZDF suggested 31% of respondents believed Mr Steinmeier had won, and 28% said Mrs Merkel.
A Forsa poll suggested 37% said Mr Merkel was the winner, against 35% her rival.