Michael Phelps officially earned the crown of the most medalled Olympian in history here in London on Tuesday, as he won his 18th and 19th medals.

First, he earned silver in the men's 200-metre butterfly, beaten to the gold by South Africa's Chad le Clos. Then Phelps came back to claim gold as part of the men's 4-by-200-metre freestyle relay. And he has several chances to win more over the coming days.

Meanwhile, his teammate Allison Schmitt and China's Ye Shiwen both set Olympic records to win gold in the women's 200-metre freestyle and 200-meter individual relay, respectively.

In women's synchronised diving, China again dominated the pool, as Chen Ruolin and Wang Hao won gold over Mexico's Paola Espinosa and Alejandra Orozco. But the American women's team upset the Chinese favourites to win gold in gymnastics on Tuesday. The Chinese team ended up in fourth place.

Fifth seed Jo-Wilfried Tsonga of France held out to win the longest ever Olympic tennis match on Tuesday. After four hours, Tsonga beat Canada's Milos Raonic 6-3, 3-6, 25-23 to reach the third round. Meanwhile, Venus Williams moved a step closer to her fourth Olympic gold after beating Canada's Aleksandra Wozniak.

Germany dominated today's equestrian events, winning both the team and individual gold medals. America's Vincent Hancock set a record to take gold in the men's skeet shooting. And 21-year-old Alaaeldin Abouelkassem from Egypt won Africa's first ever fencing medal, a silver in the men's individual foil.

So at the end of Day 4 China still tops the medals chart with 23 total medals, 13 of them gold. The USA also has 23 medals, but 9 golds. And France is still third with 4 golds.

The big event on Wednesday is the men's all-round individual gymnastics final. Medals are also up for grabs in swimming, diving, road cycling, rowing, canoeing, table tennis, fencing, judo, weightlifting and shooting.