Europe's Economic Commissioner has slammed former Greek finance minister Yanis Varoufakis for his negotiating style during the Greek crisis, saying on Thursday he preferred working with his successor. "Mr Varoufakis wasn't (at the Eurogroupe meetings of finance ministers) to negotiate," Commissioner Pierre Moscovici said at a conference. "I'm happy that Euclid Tsakalotos is the new finance minister, because he is somebody we know," he added.