Michael Phelps tonight became the most decorated Olympian of all-time after claiming a silver and a gold at the Aquatics Centre.
The American finished second in the 200m butterfly - inches 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 4x200m freestyle relay.
Phelps was on the final leg and was afforded a hero's reception as he powered to victory after being put in pole position by Ryan Lochte, Conor Dwyer and Ricky Berens.
The understated 27-year-old told BBC Sport: "The 200m butterfly didn't really go the way I wanted.
"I have had the privilege of getting to know Chad over the last year and he is a hard worker and a very talented kid.
"I can't be too upset. The time was decent for me."
He added: "The important thing was for me to come back with these (relay) guys and we did it.
"It's my first medal of the meet so I'm very happy."
Allison Schmitt of the United States won the women's 200 metres freestyle final in an Olympic record and 16-year-old Chinese sensation Ye Shiwen clinched her second gold of the Games in the 200 metres individual medley.