Alistair Brownlee returned from an ankle injury to win the World Triathlon Series race in Kitzbuehel, Austria.
Brownlee, 25, has not raced in the last two events since a win in San Diego but he clocked a time of 55 minutes 23 seconds for victory.
The 2012 Olympic gold medallist was 37 seconds ahead of second-placed Spaniard Mario Mola, with Sven Riederer of Switzerland third.
Younger Brownlee brother Jonny missed the race with a stomach bug.
Alistair Brownlee's victory saw him climb to joint sixth in the rankings table, level with his sibling, with three events - including the Grand Final in London on 11-15 September - to go.
"I'm glad Jonny wasn't here, it would have been a lot harder race for me," he said.
"Once I was riding there was nothing I could, my stomach was an absolute wreck.
"I was just trying to keep a nice steady rhythm. Fortunately it was enough."
But the 23-year-old, who missed the first two events of the season because of injury, came down with the bug on Friday and was confined to bed on the eve of the race.
Because of the difficult nature of the course, it was decided that he would not be strong enough to compete.
The race started with a 750m swim in Schwarzsee lake followed by an 11.55km cycle ride that featured gradients reaching 22% and a 2.55km run over uphill trails.
Each winner of a World Series event gets 800 points, second place 740 and third 685, while higher points are on offer in the Grand Final, with the victor picking up 1,200 points.
The champion is decided based on competitors' best four World Series finishes plus their Grand Final result.