On this day: Died June 21, 1969: Maureen Connolly, American tennis player

(Reuters) - American Maureen Connolly's career lasted only four years in the early 1950s but it was enough time for "Little Mo" to make a big impression in the tennis world.

Feared and revered for her aggressive style, the 5ft 4in San Diego native's firepower saw her nicknamed in reference to the U.S. Navy battleship USS Missouri -- which was dubbed "Big Mo."

Connolly exploded onto the scene in 1951 by winning the U.S. Championships at 16 years, 11 months and 19 days -- at the time the youngest winner of the tournament. She repeated her success over the next two years.

A hard-hitting baseliner who hated losing, Connolly added the Wimbledon title to her trophy collection in 1952 and would cement her place in history as one of the game's greats the following year.

After splitting with her coach Eleanor Tennant to work with Australian Davis Cup captain Harry Hopman, she became the first woman to win all four majors in a single year -- a feat only Margaret Court (1970) and Steffi Graf (1988) have matched.

"DARK DESTINY"

Despite dizzying success, Connolly was aware of the negative aspects of her tennis career.

"I have always believed greatness on a tennis court was my destiny, a dark destiny... where the court became my secret jungle and I a lonely, fear-stricken hunter," Connolly wrote in her 1957 autobiography "Forehand Drive."

"I was a strange little girl armed with hate, fear, and a Golden Racket."

Connolly's career was cruelly cut short at its peak in 1954 after she retained her French Open and Wimbledon titles, as she indulged in another of her passions -- horse riding.

Riding Colonel Merryboy, a stallion given to her by the city of San Diego, Connolly was hit by a truck and sustained broken bones as well as severed arteries in her right leg.

Despite the best efforts of doctors, she did not fully recover and retired having won 12 major trophies, including two women's doubles crowns and a mixed doubles title.

"I don't have fond memories of tennis," she was quoted as telling a reporter once. "Tennis can be heavy if you dedicate your entire life to it. This can make you bitter if you have nothing but training and matches in your head.

"Tennis is a great game but I leave it with no regrets. I had the life of a champion, full of travels, meetings... Now I aspire to a more peaceful life, a housewife's life. I'm happy."

Connolly went on to marry Norman Brinker, a member of the 1952 U.S. Olympic equestrian team, and had two daughters.

Like her career, Connolly's life came to a premature end at the age of 34 in 1969 when she died of cancer, having been diagnosed with the disease three years earlier.

(Reporting by Shrivathsa Sridhar in Bengaluru; Editing by Ken Ferris)