By Nick Mulvenney

RIO DE JANEIRO (Reuters) - Spaniard Ruth Beitia leaped into the Rio night to win Spain's first Olympic gold medal in women's athletics and claim her first global outdoor high jump crown at the age of 37 on Saturday.

The three-times European champion cleared 1.88m, 1.93m and 1.97m at her first attempts and became the oldest Olympic champion in the jumps on countback when all four remaining athletes failed to get over two meters.

"I'm happy," she said. "Never did I think I'd be competing again after the London Olympics. My dream has become a reality."

Mirela Demireva of Bulgaria took silver ahead of 32-year-old former world champion Blanka Vlasic of Croatia, who added bronze to the silver she won at the 2008 Beijing Olympics.

American mother-of-three Chaunte Lowe was the one jumper of the quartet who cleared 1.97m to miss out on a medal.

Like 32-year-old Lowe, Beitia was appearing at her fourth Olympics having finished 16th in Athens, seventh in Beijing and fourth in London.

She always looked like continuing her upward trajectory in Rio after clearing 1.88m with a minimum of fuss.

Extending her arms out in front her body and twitching her fingers before starting her run, Beitia charged toward the bar with her pony tail bouncing behind her before also successfully clearing the next two heights.

Beitia became the oldest medalist in the women's high jump by six years and was also a year older than Heike Drechsler when the German won long jump gold at the Sydney Olympics.

"I'm aware that I'm 37 years old," she said. "I think I'm one of the oldest women to win an Olympic gold medal. Of course, I'm very proud to still be continuing up to now. Even at my age, I have the same enthusiasm and happiness."

Twice world champion Vlasic also made her Olympic debut in Athens in 2004 but missed the London Olympics because of the Achilles problem that has blighted the latter part of her career.

Vlasic returned to competition this year but was clearly still feeling the injury in her third Games.

"This medal is a badge of honor, it's a reward for being brave given the circumstances," she said.

"The doctor didn't tell me to stay out of the Olympics, but they told me it would hurt, and it did."

London 2012 champion Anna Chicherova was unable to take part in the Games because she was suspended after a retested sample from the 2008 Olympics tested positive.

World champion Mariya Kuchina was also unable to take part because of the almost blanket ban on Russian athletes.

It was the lowest winning height in an Olympic final since 1980 and two athletes jumped higher in the Rio heptathlon, but that did not bother the medalists.

"I am extremely happy," said Demireva, the youngest of the final four at 26.

"It is a dream come true. Since I got selected for the Olympic Games in Rio I knew they would be my Olympics. I put all my heart and emotion into this silver medal."

(Editing by Ed Osmond/Greg Stutchbury)