American swimmer Lia Neal secured her second Olympic berth thanks to a personal best performance. Her appearance in Rio de Janeiro will be an historic one.

The 21-year-old Neal, who hails from Brooklyn, N.Y., made the U.S. squad along with fellow Stanford University swimmer Simone Manuel. Their presence in Rio will be the first time two African-American swimmers have competed at the Olympics for Team USA.

Four years ago in London, Neal swam the third leg of the 4x100-meter freestyle to help the Americans earn the bronze medal. She was selected to swim in the final after a strong swim in the preliminary heats.

At the recent Olympic Trials in Omaha, Neb. Neal punched her ticket to another Olympics by finishing fourth in the 100-meter freestyle with a time of 53.77 seconds — a personal best.

In most events at the Trials, the top two finishers advance to the Olympics. But in the 100m freestyle, the top six finishers can be named to the squad because of the relays.

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"I'm a two-time Olympian and I couldn't have done it without the support of my family, coaches, and friends. I am thankful beyond words," Neal wrote on her Twitter account. She pinned the July 3 tweet so that it appears at the top of her feed.

Neal began swimming at age 6 after her friends had begun taking lessons. Fifteen years later, Neal has morphed into a relay swimmer with an impressive resume.

Aside from her London Olympics bronze medal, Neal has silver medal from the 2015 world championships in the 4x100-meter mixed medley relay, a bronze from the same meet in the 4x100-meter freestyle, and two medals from the 2012 short course worlds: gold in the 4x100-meter freestyle and bronze in the 4x100-meter medley.

Neal also won the gold medal as part of the 4x100-meter freestyle at the 2015 World University Games.

With a resume like that, it's no wonder Neal finds herself on another Olympic team, with a relay medal square in her sights.

"I think it's great for the sport of swimming to become more diverse and also for kids to become water safe," Neal told a Stanford-area television station during a recent interview, a few days before the U.S. swim team departed for pre-Olympics training camps in Texas and Puerto Rico. 

Neal has come a long way since swimming her first laps at age 6 and her days of swimming at Manhattan's Asphalt Green. And she made history in 2012 when she was the first black swimmer to compete on a U.S. relay team at the Olympics.

She's hoping to add another piece of hardware in Brazil next month.