Germany's main opposition party named a feisty former finance minister to lead its bid to unseat Chancellor Angela Merkel from the helm of Europe's top economy in elections next year. Three leading members of the centre-left Social Democratic Party (SPD), including the candidate himself, Peer Steinbrueck, jointly announced their pick to reporters, ending weeks of speculation. Steinbrueck, 65, who previously served as Merkel's finance minister in a grand coalition, must win over voters amid polls showing consistently widespread approval for Merkel as she tackles the eurozone crisis. "I accept this challenge in order to win the next federal elections, with and for the SPD," Steinbrueck told the joint news conference. "That is the demand, that is the ambition. We want to displace this government. It's obvious that this government will not be returned in a year," he said. "But we don't just want it to be partly replaced, we want it to be replaced by a red-green government," he said, referring to a coalition between his SPD and the Green party. Steinbrueck served as finance minister during Merkel's first term as chancellor and the two worked closely together to overcome the financial crisis caused by the 2008 collapse of US investment bank Lehman Brothers. Steinbrueck beat off competition from party head Sigmar Gabriel and another SPD heavyweight and former foreign minister Frank-Walter Steinmeier, who ran unsuccessfully against Merkel in 2009.