By Annika Breidthardt
BERLIN (Reuters) - Angela Merkel's center-left challenger in Sunday's election mocked the chancellor on Thursday as a timid driver steering Germany round in circles and urged his supporters to disregard polls predicting her victory.
Peer Steinbrueck's Social Democrats (SPD) are trailing Merkel's conservatives by at least 10 percentage points and he has sharpened his attacks on the woman Germans nickname 'Mutti' (Mummy) as election day looms.
At one of his last big campaign rallies, on the sprawling Alexanderplatz square in central Berlin, Steinbrueck contrasted what he derided as Merkel's excessive caution and lack of ambition with his own straight-talking style of leadership.
"She likes to drive around roundabouts. That way you don't hit anything... You drive without accidents. I don't do that, I admit," Steinbrueck, a feisty public speaker, told the rally.
"But the moment you set a direction, the moment you don't just administer this country but also decide its political direction, you also cause offence, you provoke. At least with me you know what you get, in contrast to the last four years."
The crowd waved placards bearing the SPD election slogan "We win together" and flags with the party's red and white colors.
Merkel's steady, risk-averse approach to governing Europe's largest economy helps to explain her high personal ratings of around 65 percent. Her public image as a safe pair of hands has dominated her Christian Democrats' (CDU) election campaign.
In contrast to the reassuring, stolid Merkel, Steinbrueck, 66, a former finance minister, is known for his quick wit but also can come across as arrogant and abrasive. He has committed several gaffes during the campaign.
Steinbrueck dismissed the opinion polls, which put the SPD on 25-28 percent against 38-41 percent for the conservatives.
"It's not the pollsters, nor the wishful thinking of politicians... but you voters who decide," he said.
The mood of defiance is running strong in a party that was last in power as junior partner in a 'grand coalition' with the conservatives under Merkel from 2005 to 2009.
"I don't believe the polls. It will be a really tight race. The campaign isn't over yet. I don't believe the CDU will do as well as they think," said student Christian Lohse, 25.
Many political analysts say another left-right coalition is the most likely outcome of Sunday's election, though Steinbrueck has said he would not serve again in a Merkel-led government.
(Writing by Gareth Jones; Editing by Robin Pomeroy)