The CEO of Italy’s largest utility firm says he’s been left stunned by the tactics deployed by Spain’s Iberdrola, amid a bitter feud over Brazil’s largest power distributor.

Europe’s top two utilities, Enel and Iberdrola, are in the midst of a fierce battle to secure the assets of Brazil’s Electropaulo. The South American grid operator became one of the world’s most prized power assets last month, prompting Italy’s Enel and Spain’s Iberdrola to lock horns and try to outbid one another for control of the company.

Tensions were frayed further when Iberdrola wrote to the European Commission in April, accusing state-controlled Enel of using the weight of the Italian government to allow it to make investment decisions it would otherwise not be able to submit.

Speaking on the sidelines of the St. Petersburg International Economic Forum (SPIEF), Enel CEO Francesco Starace told CNBC Friday that he could not understand the “testosterone” fueled efforts of Iberdrola.

When asked whether he was disappointed by the Spanish firm’s decision to write to the European Commission, the executive arm of the EU, he replied: “No I’m not disappointed, I’m a little bit surprised. They seem to be so aggressive on this bid (when) it is just a nice deal, it is not the deal of the century or the deal of the year even.”

“We are a large company, they are also a large company, we are not going to die or whatever if we don’t make this deal,” he added.

Brazil is seen as a strategic market space for Iberdrola because it helped drive a 24 percent rise in core profits over the first three months of the year.

Meanwhile, for Enel, a deal to secure Electropaulo’s assets would reportedly double its client base to approximately 17 million.

A spokesperson for Iberdrola was not immediately available for comment when contacted by CNBC.