Adds Horner reaction paras 10-13

MIAMI, May 2 (Reuters) - Formula One handed Miami the longest race contract in the sport on Friday, securing the grand prix until 2041 with a 10-year extension on top of an existing decade-long deal.

The first of three U.S. rounds on the 24-race calendar -- the others being Austin's Circuit of the Americas and Las Vegas -- is being held at the Hard Rock Stadium this weekend.

It was first held in 2022.

Formula One chief executive Stefano Domenicali said Formula One wanted to think big and the extension marked "a strategic milestone of enormous importance".

"In this moment of an incredible period of growth of Formula One, we want to make sure that we stay tuned and work together with the best partner that we have," the Italian told a press conference.

"Miami will be part of our bigger strategy to be even stronger in the United States of America. This is a place where it is crucial to be.

"We are getting bigger and bigger but we are still very small if you compare to the biggest sport franchise in the U.S... this will help us to grow in the right segment, in the right direction."

Liberty Media-owned Formula One has boomed in popularity, particularly in the Americas where it has plenty of potential for growth, thanks largely to the hit Netflix docu-series 'Drive to Survive'.

A Hollywood movie 'F1', starring Brad Pitt, is due for release next month.

Red Bull boss Christian Horner said the extension was for "an insane amount of time" but was sure to help Formula One's growth.

"Formula One really struggled in America a few years ago. Now we're here with three grands prix and Miami is one of the best. It's one of the landmark races that everyone wants to be at," he told Sky Sports television.

"With that amount of longevity maybe they can invest a little bit in the track as well.

"As an experience, to come to this race is definitely one to be on the bucket list."

Domenicali said also that there was a lot of interest in the U.S. media rights package, currently held by ESPN, with discussions ongoing. He gave no details.

Miami GP promoter Tom Garfinkel said the extension would help build a fan base and turn the venue into a motorsport hub.

The Hard Rock Stadium is home to the NFL Miami Dolphins and also a venue for soccer -- including next year's World Cup -- and concerts. The surrounding complex also hosts tennis and track day events.

"This has a huge impact, both financially on South Florida but also locally here in the Miami Gardens community," said Garfinkel.

"When you take someone to an event who's a casual fan who may not love the sport, that's when they really fall in love and become more of an avid fan," he said.

"So we believe if we're here doing that year after year, we're just going to grow more fans here in the United States."

(Reporting by Alan Baldwin in London, editing by Toby Davis)

((alan.baldwin@thomsonreuters.com; +442075427933;))