Justin Gatlin on criticism by Lilly King: I've done what I need to do

American sprinter Justin Gatlin has a message for United States swimmer Lilly King: Not so fast.

King, 19, was critical earlier this week about the Olympic participation of athletes -- including Gatlin -- who have tested positive for banned substances in the past. Gatlin has twice been caught using banned substances, but is considered the top threat to unseating Jamaican star Usain Bolt in the 100-meter final Sunday.

"I don't even know who Lilly King is," Gatlin said after winning his 100-meter heat Saturday in 10.01 seconds -- the best time of the day. "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."

The 34-year-old Gatlin, who won gold at 100 meters at the 2004 Olympics, first tested positive for amphetamines, though arbitrators determined he didn't use them for doping but to treat attention deficit disorder. The second came for excessive testosterone in 2006 and resulted in a four-year ban.

"I've worked hard, just like everybody else, and I get tested, just like everybody else," Gatlin said Saturday. "I'm back here. I believe in the system. I hope everybody else believes in the system too."

King originally made her comments after the Court of Arbitration for Sport allowed Russian swimmer Yulia Efimova to compete in Rio after a last-minute appeal of her doping ban.

When asked about Gatlin, King remained critical.

"Do I think people who have been caught doping should be on the team? They shouldn't," said King, who beat Efimova to win the gold medal in the women's 100-meter breaststroke. "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."