Phelps, 31, won his 22nd gold - more than any other Olympian - as fellow American Lochte, 32, faded to a fifth-place finish in Rio.

Phelps finished almost two seconds clear of Japan's Kosuke Hagino, with China's Shun Wang taking bronze.

Briton Dan Wallace, 23, came eighth.

Phelps, who posted a time of one minute 54.66 seconds, has won more than twice as many gold medals as anyone else, with former Soviet gymnast Larisa Latynina second on the list with nine.

The American, who retired after London 2012 before returning to the sport in 2014, also has two silver medals and two bronze.

Four of his 22 golds have been won in Rio, where Phelps has added 200m medley success to wins in the 200m butterfly, 4x100m freestyle relay and 4x200m freestyle relay.

He could also win his fourth successive gold in the 100m butterfly after qualifying for Saturday's final shortly after his 200m medley victory.

Analysis - 'Phelps destroyed the field'

Adrian Moorhouse, 1988 Olympic 100m breaststroke champion, on BBC One: "What a winner. It's been a privilege to watch every one of his gold medals, but I don't think I've seen one as emotional as that one. He destroyed the field. It was stunning."

Rie Kaneto won Japan's seventh gold medal at Rio 2016 as GB's Chloe Tutton narrowly finished outside the medals in the women's 200m breaststroke.

Kaneto, 27, beat controversial Russian swimmer Yulia Efimova - allowed to compete at Rio after successfully appealing against a doping suspension - into silver.

China's Jinglin Shi won bronze, just six one-hundreths of a second ahead of fourth-placed Tutton.

Her British team-mate Molly Renshaw, 20, finished sixth.

Afterwards Tutton appeared to criticise the decision to allow 24-year-old Efimova, also silver medallist in Monday's 100m breaststroke, to compete in Brazil.

"Being in fourth place is a bit gutting, no matter who is in front of you. I would've preferred it to have been a completely clean Games," the 20-year-old Welsh swimmer said.

"I couldn't help who was here. I'm not happy with it, but it's just the way it is."

Earlier, Ben Proud set a British record to reach the men's 50m freestyle final.

Commonwealth champion Proud, 22, swam a time of 21.54 seconds to qualify fifth fastest for Friday's final (02:44 BST Saturday).

Murphy seals another USA victory

The United States won the men's 200m backstroke title for the sixth Olympics in a row with Ryan Murphy taking gold.

Murphy, who also won the 100m backstroke on Monday, sealed the victory in a time of 1:53:62.

Australia's Mitchell Larkin finished second and Russia's Evgeny Rylov set a new European record as he won bronze.

Murphy follows in the footsteps of fellow Americans Brad Bridgewater (1996), Lenny Krayzelburg (2000), Aaron Peirsol (2004), Lochte (2008) and Tyler Clary (2012) in winning the 200m title.

(BBC)