The US is still ahead in overall medal count in the race for the top spot in the medal race on day 8 of the ongoing London 2012 Olympics after overtaking China on day 6 of competition.
The US is struggling to maintain a slim lead over China in overall medal standing with 54 medals against China's 53 after day 8 of competition.
The US is also ahead in gold medal production with an eight-day total of 26 and leading China with just one gold medal
But China is still ahead in silver medal production with 16 silvers while the US has only 13. The US is ahead on bronze medal count with with a three-medal edge.
Host Great Britain is far third in overall medal ranking with a total of 29 comprising of 14 golds seven silvers and eight bronzes.
In the race for gold, Republic of Korea won nine gold medals while France snatched eight in the past eight days of competition.
Germany, Italy and Kazakhstan shared five gold medal each. North Korea has four gold medals while Russia, Netherlands, South Africa and New Zealand shared three golds each.
Japan, Cuba, Hungary, Poland and Ukraine shared 2 medals each. 15 other countries share one gold medal each.
Michael Phelps after winning gold: Phelps of the United States celebrates after winning the gold in the Men's 4 x 200m Freestyle Relay final on Day 4 of the Games.
Meanwhile ace Olympian Michael Phelps has bowed out of the Olympic Games with 18 gold medals and 22 overall in swimming at the end of London Olympics swimming competition
Phelps struggled in his first attempt to capture a gold medal in the early stage of competition, bowing to Chad le Clos of South Africa and finishing fourth in the 200m Butterfly.
Phelps has earlier talked of retirement, saying he does not intend to swim after reaching the age of 30. The super swimmer is now 27.
'I don't want to swim after I turn 30 and that is in three years and I don't want to swim for another three years.
After the competition, Phelps told his coach Bob Bowman how he looked up to Michael Jordan and how he became the best swimmer of all time.
'I would be past 30 by the time of the next Olympics. I have achieved what I wanted to achieve; Bob and I have somehow been able to do every single thing.
'If you can say that about your career then it's time to move forward, time to move on to other things.
'I finished my career how I wanted to.'
US President Barack Obama led millions of well wishers around the world on the outstanding achievement of the world's greatest swimmer.