By Shida Chayesteh

COPENHAGEN, March 20 (Reuters) - Novo Nordisk should still be able to introduce its long-acting insulin Tresiba on the U.S. market before rival products, despite being hit by a delay, the CEO of the Danish pharmaceutical company said on Thursday.

In February 2013, U.S. regulators unexpectedly refused to approve Tresiba until the group conducted extra tests over potential heart risks, dealing a major blow to one of Novo Nordisk's key products as well as to its share price.

"We judge that we still have an opportunity to launch Tresiba in the United States, if we are successful in the trials, before any significant competitive products are being entered into the market," Lars Rebien Sorensen told the company's annual general meeting.

French drug maker Sanofi recently sued Eli Lilly , delaying the U.S. firm's introduction of a generic version of Sanofi's Lantus insulin product, a rival to Tresiba.

The suit is seen as positive for Novo Nordisk, the world's largest insulin producer, because it gives the company an opportunity to bring Tresiba to the market before a generic version of Lantus is launched.

"You will have noticed a significant positive development of our share price. It was not necessarily due to the share split but rather due to our competitors," Sorensen said.

Novo Nordisk lost about $14 billion in market value after the decision by the U.S. Food and Drug Administration (FDA) was published. It carried out a 5-1 split of its shares in December last year.

Goran Ando, who took over as chairman of the board at Novo Nordisk last year, told Reuters that getting Tresiba approved by the FDA was one of the most important short-term goals for the group.

"I think perhaps the biggest challenge (in 2014) will be to keep up the growth in the U.S., which has been a growth engine for us, without having our new long acting insulin Tresiba on the market there," he told Reuters ahead of the annual general meeting.

The Danish company expects overall sales to grow by 8-11 percent in 2014, below its average 13 percent growth rate over the last ten years. Novo Nordisk had sales of 39 billion Danish crowns ($7.2 billion) in 2013 in the United States compared with 34.2 billion crowns a year earlier.

($1 = 5.3662 Danish Crowns) (Editing by Mark Potter)