BERLIN -- Chancellor Angela Merkel's rival questioned her strategy to combat Europe's debt crisis as he faced the German leader Sunday in their only televised debate of the country's election campaign, saying that there is no point in applying a "deadly dose" of austerity. Merkel insisted that it's essential to stick to her course.

Center-left challenger Peer Steinbrueck went into the 90-minute debate facing a daunting poll deficit before Sept. 22 parliamentary elections. The event offered him an opportunity after a summer in which the opposition has struggled to land any blows on the popular conservative incumbent.

Merkel has benefited from a healthy economy and perceptions that she's managed Europe's debt crisis well. She touted that record at the start of the debate, pointing to high employment and portraying Germany as "the motor of growth" and "the anchor of stability" in Europe.

Merkel's finance minister said last month that there will have to be a third aid program for Greece after the current one ends last year. Germany is the biggest contributor to the 17-nation eurozone's rescue programs, and Merkel has pursued a hard-nosed approach - insisting that struggling countries get their finances in order and enact economic reforms.

Steinbrueck asked "whether, with the announcement of a third Greek package, we shouldn't admit to ourselves that the crisis strategy to date - largely put forward by this government - has failed." He argued that "what is lacking is a rebuilding program, what is lacking is a growth impulse."

He said that there has to be austerity, "but not in a deadly dose for these countries."

Merkel retorted that Steinbrueck's Social Democrats have voted for the various measures she has put forward in the crisis - including a European budget-discipline pact - and insisted that her approach is the way to fix the eurozone's troubles.

"What is important now is not to show false solidarity, but to follow a principle - and this principle is ... solidarity and responsibility, and if we do not follow this through we will see that these countries don't regain more jobs," she said. She pointed to efforts that have been made to encourage growth in Europe.

On the home front, Steinbrueck said he wants to ensure greater "social justice," introducing a mandatory national minimum wage - which Merkel rejects, preferring sector-by-sector agreements between employers and employees.

He also defended plans to raise income tax for top earners. Merkel argued that raising taxes would ultimately risk endangering jobs, and pointed to the government's high tax take at present - "we must get by with that and we can get by with that."

Recent surveys have given Merkel's conservative bloc a large lead over Steinbrueck's Social Democrats and suggested that her current center-right coalition can hope to win re-election.