(CNN) -- If at first you don't succeed, try, try, try, try, try again.
That's the message from 64-year-old endurance swimmer Diana Nyad, who achieved her lifelong goal of conquering the Straits of Florida.
On Monday, she became the first person to swim from Cuba to Florida without a protective cage, willing her way to a Key West beach just before 2 p.m. ET, nearly 53 hours after jumping into the ocean in Havana for her fifth try in 35 years.
Nyad pumped her fist as she walked onto the beach toward an awaiting medic before being guided to an ambulance.
Diana Nyad 'getting a little cranky now'
"I got three messages," an exhausted and happy Nyad told reporters.
"One is we should never ever give up. Two is you never are too old to chase your dreams. Three is it looks like a solitary sport, but it's a team," she said.
Dozens of onlookers -- some in kayaks and boats, many others wading in the water or standing on shore -- gathered to cheer her on as she finished the more-than-100-mile swim.
Diana Nyad breaks distance record
Diana Nyad to try again
It was a long-awaited triumph for Nyad, who was making her fifth attempt since 1978 and her fourth since turning 60.
The first four tries were marked by gut-wrenching setbacks; if the rough, strength-sapping seas didn't force her to quit, an hours-long asthma attack or paralyzing and excruciating jellyfish stings did.
But for this swim, besides donning a suit meant to protect her against her jellyfish nemesis, she wore a special mask to prevent jellyfish stings to her tongue, a key factor in her failed attempt last year.
She and her support team didn't encounter many jellyfish this time. But she had plenty of other challenges, and with roughly 2.5 miles left to go, she paused in the water to thank her crew.
"This is a lifelong dream of mine, and I'm very, very glad to be with you," she said late Monday morning, treading water as she spoke to her team on the five boats gathered around her, according to the team's website.
"You pulled through; you are pros and have a great heart. So let's get going so we can have a whopping party," she said, according to the website.
Nyad's age was one of the intriguing aspects of her latest attempts. Nyad, who was 29 when she first tried, said last week that she wanted to show that "you can dream at any age."
"This time, I am 64. So, the years of my life are shorter to the end," she said at a news conference in Havana on Friday. "So this time I am, all the way across ... going to think about all those life lessons that came up during the swim."
Fatigue almost seemed poised to derail her again early Monday.
About 7:30 a.m. ET, she was slurring her speech because of a swollen tongue and lips, her support team reported on its website.
As the team called her around dawn for her first feeding since midnight, she took longer than normal to reach the support boat, the report said.
Divers swam ahead of her, collecting jellyfish and moving them out of Nyad's path.
Swimmer's challenge: Cross 103 miles of shark-infested water
When instructed Monday morning to follow the path that's been cleared for her, she flashed her sense of humor, replying, "I've never been able to follow it in my life," according to the website.
Nyad's home stretch followed an overnight in which she became so cold, the team didn't stop her for feeding until first light "in the hopes that swimming would keep her warm," the website said.
Every stroke she swam put her deeper into record territory. On Sunday night, she broke Penny Palfrey's record for the farthest anyone has managed on the trek without a shark cage.
In 1997, Australian Susie Maroney completed the swim from within a shark cage. She was 22 at the time.
Nyad set out from Havana at 8:59 a.m. Saturday with a crew of 35, including divers to watch for sharks.
In her first attempt to cross the Straits of Florida in 1978, rough seas left her battered, delirious and less than halfway toward her goal.
She tried again twice in 2011, but her efforts ended after an 11-hour asthma attack and jellyfish stings.
Last year, she abandoned an attempt about halfway through after severe jellyfish stings and a lightning storm put her in danger.
Nyad was a swimming sensation before these attempts. In the 1970s, she won multiple swimming marathons and was one of the first women to swim around the island of Manhattan.
Nyad said she was 8 years old when she first dreamed about swimming across the Straits of Florida. At the time, she was in Cuba on a trip from her home in Florida in the 1950s, before Fidel Castro led a Communist takeover in Cuba and the country's relations with the United States soured.
The Los Angeles woman had said this was going to be her final attempt.