Double Olympic champion Alistair Brownlee was disqualified as Britain’s Alex Yee won the men’s race in the World Triathlon Series event in Leeds.
Brownlee was seen dunking Chase McQueen during the swimming leg of the event in Roundhay Park.
He later tweeted he that was “very embarrassed” by the disqualification for an “unintentional” action.
Earlier, Maya Kingma of the Netherlands won the women’s race ahead of Britain’s Jess Learmonth.
It was 23-year-old Yee’s first World Series win, with Jonny Brownlee finishing in ninth.
After the disqualification, Alistair Brownlee appeared to admit defeat in his bid to make Britain’s squad for the Tokyo Olympics, with the 33-year-old having recently struggled with an ankle injury.
“I think GB have a great team going to the Olympics and I wish them all the best,” he tweeted.
“@Lixsanyee [Alex Yee’s] performance today was outstanding and a breakthrough.
“I’ve known my ankle needs surgery for a little while. My focus will be on getting healthy again and then long distance triathlon in the future.”
His brother Jonny, two years his junior, was selected for his third Olympics near the end of 2020.
Yee broke away in the early stages of the 10k run that followed the 1500m swim and 40km cycle race, finishing an impressive 25 seconds ahead of Morgan Pearson of the USA, with Belgium’s Marten van Riel in third place.
‘I needed a miracle’
Alistair Brownlee had missed the World Series event in Yokohama in May, and chose not to take part in the run section of the World Cup race in Sardinia last weekend because of his ankle injury.
“That [Sunday] was a really tough day,” he told BBC Sport. “I only knew I was disqualified on the last lap so it was a bitter end to it.
“In the middle of the swim, anything can happen. I’m in the middle of a stroke and I can guarantee that as bad was done to me 10 seconds before and 10 seconds after. It is a subjective field of play decision, but it is what it is.
“I was pretty sure that would be my last World Series race. I have struggled in the last three or four months with injury – I needed a miracle today. I have done everything I can and I needed some luck but I didn’t get it.”
His brother called the swim “absolutely awful”, and added: “When the swim is not fast enough we end up swimming next to each other. There are too many good swimmers next to each other, so it is not swimming, it’s fighting.
“I know he wouldn’t have meant to do anything but it is just the fact that when the swims are like that you end up catching the arms.
“I didn’t feel at my best but fair play to Yee, it was incredible and I am sure it will be the first win of many.”
Learmonth misses out in closing stages
In the women’s race on the same course, Kingma edged out Learmonth after pulling away from the Leeds-based triathlete in the closing seconds of the 10k run for her first World Series win.
Britain’s Sophie Coldwell was third, with Flora Duffy from Bermuda in fourth.
Learmonth will be part of the British triathlon team at next month’s Tokyo Olympics.
There were four Britons in the first seven places, with Lucy Charles-Barclay and Beth Potter finishing fifth and seventh respectively.
Charles-Barclay, an ironman specialist competing in her first World Series event, led after the opening 1500m swim before Kingma, Learmonth and Caldwell pulled clear in the cycling leg.
More reaction to men’s race
Alex Yee: “That’s the best feeling I’ve probably ever had in my life and so special to do it in front of fans,” said the 23-year-old from Lewisham following the event, which took place in front of a crowd of about 4,000 in the Brownlees’ home city.
“I have so much respect for the guys I am battling against. The best person will go because I trust the governing body to make the right decision.”
Mike Cavendish, performance director for British Triathlon: “We meet on Tuesday, and again a couple of weeks later. There are no guarantees but he [Yee] is in a good spot.
“We would have loved to see Alistair closer to the front but he has been carrying an injury. We will talk to Alistair, see where his head is at, talk to Alex as well and put all that into the mix.”