The 18-year-old clocked a time of 1 min 12.50sec to shave more than a second off his former best mark set just a few hours earlier in this morning’s heats.

Victory sees Serrano end Colombia’s long wait for a Paralympic champion, stretching back coincidentally to Pedro Mejia’s triumph in the men’s 100m breaststroke at the 1980 Games in the Dutch city of Arnhem.

"This is the happiest day of my life," he said.

"I feel strong.

"I love Rio.

"I raced as hard as I could this morning but I knew I could go quicker tonight.

"I have trained so hard."

Australia’s defending champion Blake Cochrane secured silver in 1:18.66, with China’s Hong Yang claiming bronze in an Asian record time of 1:20.21.

Army Sergeant Elizabeth Marks - injured while on duty in Iraq in 2010 - began a gold rush for the United States in the women’s 100m breaststroke SB7, posting a world record time of 1:28.13.

Team-mate Jessica Long took silver in 1:32.94 for her third medal in as many days, while The Netherlands' Lisa den Braber was third in 1:34.66.

There were a further three gold medals won by the US today, the first of which came courtesy of Roy Perkins' victory in an incredibly tight men’s 50m butterfly S5.

The Beijing 2008 Paralympic gold medallist finished in 35.04 to beat China’s He Shiwei by 0.21 seconds.

Defending champion Daniel Dias surprisingly had to settle for third spot in 35.62, ending the home favourite’s bid to become the most decorated male Paralympian of all time, out-right, at these Games.

With six of his nine events remaining, the 11-time Paralympic champion can now only equal Swedish shooter Jonas Jacobsson’s total of 17 gold medals.

Among the other American winners was world champion Rebecca Myers, who registered a time of 2:24.66 to hold off Uzbekistan’s Fotimakhon Amilova in the women’s 200m individual medley SM13 and claim her second gold of Rio 2016. 

Amilova came second in 2:25.23, while compatriot Shokhsanamakhon Toshpulatova won her first Paralympic medal with bronze in 2:27.31.

Bradley Snyder completed the US’s quartet of gold medals, coming away with the men’s 400m freestyle S11 crown in 4:28.78 to secure his second consecutive Paralympic title in the event.

Like Marks, Snyder also became impaired while on duty for his country in the US Navy, winning the title at London 2012 on the one-year anniversary of losing his sight in Afghanistan.

His team-mate Tharon Drake won silver in 4:40.96, with Brazil’s Matheus Sousa 0.09 seconds behind in third.

For a full set of results, check out our live blog here.