BERLIN, Germay — The long-serving chief executive of Adidas has no intention of stepping down despite criticism as the German sportswear company loses ground to U.S. rival Nike, he told a German newspaper.

"If I no longer had the ambition and the energy, and the firm belief that I can bring the company further forward, then I would stop immediately," Herbert Hainer was quoted as saying by the Sueddeutsche Zeitung daily.

Hainer, who has been CEO since 2001, had his contract extended until 2017 last year to allow the company to work on a succession plan, but some investors have suggested a change at the top should come sooner.

Hainer admitted he had made mistakes, such as rolling out too many new golf products just as the market was contracting, but said he had been surprised by the personal criticism after a series of profit warnings.

"Suddenly, everything that was right for 12 years, was wrong," he told the newspaper.

Hainer said the world's second-biggest sportswear group was fighting back, launching the biggest marketing campaign in the company's history in February with a particular focus on the key U.S. market, even if "there are no overnight solutions there".

Adidas last week reported a better-than-expected rise in 2014 sales as it announced the sale of its Rockport shoe brand.

Helped by the 2014 soccer World Cup and the victory of the German team Adidas sponsors, Hainer said soccer sales had reached a record 2.1 billion euros ($2.4 billion), ahead of his 2 billion target.

By: Emma Thomasson; editor: David Clarke.