For the fourth Olympic Games in succession, Michael Phelps and Ryan Lochte helped the USA to a 4x200m relay gold in the pool.
Michael Phelps' record-breaking tally of Olympic gold medals is now up to an astonishing 21 after he helped the United States to a dominant victory in the 4x200m freestyle relay, the final swimming event of Tuesday at Rio 2016.
The most successful Olympian in history, Phelps regained his 200m butterfly crown earlier in the evening before returning to the pool for relay duty.
Anchoring a team that also featured Conor Dwyer, Townley Haas and Ryan Lochte, Phelps was handed a comfortable lead and brought the US home in a time of seven minutes and 0.66 seconds, ahead of Great Britain and Japan.
Phelps and Lochte have now claimed 4x200m relay gold at four successive Olympics, while Dwyer was also a member of the team that triumphed in London four years ago.
Lochte has passed Mark Spitz and Matt Biondi to become the second-most decorated American male swimmer in history behind Phelps, with 12 Olympic medals.