London Marathon 2019: Daniel Romanchuk & Manuela Schar win wheelchair races
American Daniel Romanchuk won the men's wheelchair race at the London Marathon for the first time as Britain's eight-time winner David Weir finished fifth.
Switzerland's Marcel Hug, who has triumphed in London twice, finished second and Japan's Tomoki Suzuki third.
Manuela Schar of Switzerland won the women's race.
They doubled up as the World Para-athletics Marathon Championships, meaning Romanchuk and Schar were also crowned world champions.
In the T45/46 marathon, Britain's Derek Rae won a silver medal to give Great Britain their first World Para-athletics Championships medal.
He beat his personal best by more than six minutes, finishing in two hours 27 minutes eight seconds.
"I'm super proud; I'm proud of myself and the team. It's a great individual achievement but also good to get the team going on the medal table for the World Championships," said Rae.
"We've sacrificed a lot over the last six years; myself, my wife, my team; and now we are starting to reap the rewards."
Romanchuk, 20, broke clear in the last kilometre to win in one hour 33 minutes 38 seconds, four seconds ahead of Hug.
"I am struggling to find the words. This past year has been amazing," Romanchuk told BBC Sport.
"It goes back to my youth, getting a good foundation and over the years picking up skills and the coaching. That's what has led to this."
Schar - champion in Berlin, Chicago, New York and Tokyo - cruised to victory in one hour 44 minutes nine seconds, more than five minutes ahead of four-time winner Tatyana McFadden and last year's champion Madison de Rozario.
Schar, also a winner in 2017, told BBC Sport: "I'm feeling great. It was a tough one.
"I was able to break away really easy and I had to fight the head wind the whole way
"It was my plan to break away and I'm really glad it turned out good."
Six-time Paralympic champion Weir, 39, was competing in his 20th successive London Marathon, but the defending champion's preparations were hampered by a car crash in December as well as illness.
Britain's Johnboy Smith finished 11th and Simon Lawson 15th.