Rio 2016: Lilly King 'wags the finger' and calls out at drug cheat rival Yuliya Efimova to stoke grudge match flames

Efimova was cleared to compete in Rio after winning an eleventh hour appeal against a doping ban

Lilly King, the American swimming medal hope, has become something of a cult hero in her home country after sending a message to her Russian rival Yuliya Efimova.

Efimova was cleared to compete at the Rio Olympic Games after winning an eleventh hour appeal against a doping ban.

The Russian was banned by the IOC for having previously served a suspension for doping, only to have the decision overturned by the Court of Arbitration for Sport on Saturday.

Efimova subsequently won the first women’s 100m breaststroke semi-final and celebrated by wagging her finger, apparently demonstrating that she was ‘no 1’.

King had performed the same move earlier in the day and, watching Efimova on TV, responded in king, with a gesture reminiscent of the former basketball player Dikembe Mutombo’s trademark.

The 19-year-old Evansville-born swimmer then beat her rival’s time to claim top seed position in Monday’s final.

“You wave your finger ‘No1’ and you’ve been caught drug cheating … I’m not a fan”, King later told NBC.

The crowd in Rio’s Olympic Aquatics Stadium has greeted Efimova’s appearances at the pool with boos. The 24-year-old Russian also failed a test for meldonium earlier this year but her provisional suspension was lifted by Fina, world swimming's governing body.

The showdown between the King and Efimova on Monday promises to provide this Games’ first true grudge match.