The American finished second in the 200m Butterfly - just behind South Africa's Chad le Clos - to equal the record of 18 Olympic medals set by Soviet gymnast Larisa Latynina in 1964.
He then returned in the final race of the night to take number 19 as the USA cruised to victory in the 4 x 200m Freestyle relay.
Allison Schmitt of the United States won the women's 200m Freestyle final in an Olympic record and 16-year-old Chinese sensation Ye Shiwen clinched her second gold of the Games in the 200m Individual Medley.
Germany’s Michael Jung clinched double gold - in both the Team and Individual Eventing at Greenwich Park.
Jung, riding alongside Peter Thomsen, Dirk Schrade, Sandra Auffarth and Ingrid Klimke, helped Germany land the team event earlier and he returned to edge out Sweden's Sara Algotsson Ostholt to also claim individual gold. Algotsson Ostholt would have finished first but she had the last fence down and that enabled Jung to triumph.
The team event saw Germany edge out Great Britain, whose line-up included the Queen’s granddaughter, Zara Phillips, with New Zealand third.
World champion Denisse van Lamoen was dumped out in the first round of the women's Individual Archery competition at Lord's.
Van Lamoen, who was Chile's flagbearer at the Opening Ceremony and is the country's current athlete of the year, was paired with the player she defeated for world gold last year - Georgia's Kristine Esebua - and was bundled out in straight sets.
Both players were well short of their best in the ranking round, hence lowly seedings of 31 and 34, but Esebua found her feet to win 6-0.
Esebua could not pull off another big win though, and was soon defeated by second seed Lee Sung-jin of Republic of Korea.
In the Hockey, defending Olympic women’s champions Netherlands edged out Japan 3-2, New Zealand beat South Africa 4-1, Belgium and China drew 0-0, Great Britain saw off South Korea 5-3 and Argentina lost 1-0 to the United States.
Spain, fancied to push the United States in the men’s Basketball, saw off Australia 82-70 while Russia crushed China 73-54, Lithuania outclassed Nigeria 72-53 and Brazil overcame Great Britain 67-62.
France's Tony Estanguet won Olympic gold in the individual Canoe Slalom (C1) in a time of 97.06. It was the 34-year-old's third gold medal in the event after he triumphed in Sydney and Athens.
Slovenia judoka Urska Zolnir won gold in the women's -63kg with victory over China's Xu Lili, while Republic of Korea's Kim Jae-bum beat defending Olympic champion Ole Bischof to take the gold in the men's -81kg class.
The USA clinched Gymnastics gold in the women’s Team final ahead of Russia and Romania.
History was made at a packed ExCeL with Africa's first-ever Olympic Fencing medal. But 21-year-old Egyptian Alaaeldin Abouelkassem had to settle for silver and not the gold he was really looking for - and looked like he might grab.
That went to China's world number nine Lei Sheng, who came from 13-12 down to win 15-13.
Lin Qingfeng went some way to restoring China’s reputation as a Weightlifting superpower after taking Olympic gold in the men’s 69kg.
China dominated proceedings on home soil four years ago, winning eight of the 15 golds on offer at Beijing 2008. But their mantle has been firmly challenged at London 2012, with China, DPR Korea and Kazakhstan each taking two golds from the first six on offer at ExCeL while the men’s team were yet to stand on top of the winners’ podium.
But all that changed after Lin comprehensively took the field apart with a total of 344kg, with silver going to Indonesia’s Triyatno (333kg) and Romania’s 20-year-old Razvan Constantin Martin clinching bronze (332kg).