Paralympic champion Tom Aggar has won his fourth world title with a dominant display in the arms-only single sculls in Bled, Slovenia.
The 27-year-old won in four minutes 58.01 seconds to continue his five-year unbeaten run at international level.
Alexey Chuvashev of Russia was two seconds behind, with Australia's Erik Horrie third.
Londoner Aggar had already qualified for the London 2012 Paralympic Games by making it to the final.
But he said he expected the competition to get tougher in advance of next summer.
"It was a fairly close race," he said. "Obviously the rest of the guys are improving every year and with the Paralympics next year everyone's going to get hotter again. It was a tough race but I'm pleased to come out on top."
Aggar, who has lowered the world's best time for the event on six occasions, lived up to his billing as favourite with an accomplished row.
The Brit was comfortably ahead at half-distance, easily managing the gap to Chuvashev to cruise to victory.
Aggar swam competitively at the age of five but turned his attention to water polo, playing for Middlesex.
He was playing rugby at county level at Warwick University when a fall left him a wheelchiar user.
The London-born athlete used rowing as a way to build up his leg muscles and decided to enter the British Indoor Rowing Championships in 2006 which he won.