Swimmer Takeshi Matsuda competed with his ultimate goal to beat the world's elite like Michael Phelps and win an Olympic gold medal.

He wasn't able to achieve that, but it didn't leave a bad taste in his mouth. Looking back, he treasures every moment and is proud of himself for sustaining his challenge for such a long time.

"I have no regrets," Matsuda, 32, said at a Tokyo news conference to officially announce his retirement on Monday. "I came up short with regards to winning a gold medal at the Olympics, but I cherish every single one of the four Olympic medals I won and they represent who I am."