Justin Gatlin Comments on Doping Criticism from Lilly King

American sprinter Justin Gatlin responded to criticism from 100-meter breaststroke gold medalist Lilly King on Saturday after the 19-year-old had some pointed words for the track superstar earlier in the week. 

After King said athletes with histories that include positive doping tests shouldn't be allowed to compete, Gatlin responded ahead of his attempt to end Usain Bolt's reign as the king of the 100-meter dash, per ESPN.com:

"

I don't even know who Lilly King is. She does swimming and not track and field. I'm not worried about that. I have confidence in my policies that I'm with. USADA (United States Anti-Doping Agency) has done a great job. WADA (World Anti-Doping Agency) has done a great job. I have come back and done what I need to do.

"

King's comments came on the heels of her Olympic-record (one minute, 4.93 seconds) swim in the 100-meter breaststroke that helped her defeat Russia's Yulia Efimova—who, like Gatlin, has a history of testing positive for doping, per ESPN.com:

"

Do I think people who have been caught doping should be on the team? They shouldn't. It's unfortunate that we have to see that and then it's such a tossup in between sports and in between countries. It's something that needs to be set in stone that this is what we're gonna do to settle this and that should be the end of it. There should not be any bouncing back and forth.

"

A four-time Olympic medalist, Gatlin captured gold in the 100-meter dash to go with silver in the 200-meter dash and bronze in the men's 4x100-meter relay at the 2004 Olympics in Athens, Greece. He also secured bronze in the 100-meter dash four years ago in London. 

However, the decorated sprinter has a checkered past that includes two separate bans from the sport for doping violations. According to the Los Angeles Times' Helene Elliott, Gatlin previously served a one-year ban after testing positive in 2001 for a substance that cropped up in his attention deficit disorder medication. 

Five years later, Gatlin was ordered to serve a four-year ban from 2006 to 2010 after he tested positive for testosterone. 

But now that he's back on the track, Gatlin appears to be determined to wipe away memories of his past transgressions with a strong performance in Rio de Janeiro. 

"I've come back and did what I need to do, and I've worked hard and I get tested just like everybody else and I'm back here," he said, per Elliott. "I believe in the system. Everybody else believes in the system, too."

Gatlin is slated to hit the track Sunday evening for the 100-meter dash final before he competes in the 200-meter sprint Tuesday and 4x100-meter relay Thursday.