Alistair Brownlee may not be chosen to defend his Olympic triathlon title for a second time in Tokyo after being disqualified from the World Triathlon Championship Series event in his home city of Leeds today ©Getty Images

Britain's Alistair Brownlee’s hopes of defending his Olympic triathlon title for a second time at Tokyo 2020o look slim after he was disqualified from the World Triathlon Championship Series leg on his home city of Leeds today.

The 33-year-old London 2012 and Rio 2016 champion, needing a good performance to influence the selectors after struggling with an ankle injury, was first out of the second transition, but although he completed the run he was disqualified “due to unsportsmanlike behaviour during the swim segment.”

He was reported to have "dunked" United Sates  opponent Chase McQueen during the opening leg of the competition.

Brownlee missed the previous 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 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."

Britain’s selectors have only so far chosen one male athlete for the team – Brownlee’s younger brother Jonny, the Rio 2016 silver medallist.

Meanwhile Britain’s 23-year-old Alex Yee, from Lewisham, earned an emotional and potentially crucial win as he ran well clear on the new-look Roundhay Park venue to finish in 1 hour 43 min 27 sec.

"That's the best feeling I have ever had in my life," he said.

Morgan Pearson, already selected for the United States Olympic team, was second in 1:43:52, with Marten Van Riel of Belgium third in 1:44:03 and Spain’s Fernando Alarza fourth in 1:44.12.

Jonny Brownlee was the second Briton home, finishing ninth in 1:44:43.

There was disqualification too for another man with Tokyo 2020 on his mind – Slovakia’s Richard Varga, who was found not to have taken the prescribed course in the opening swim.

Earlier, Maya Kingma of The Netherlands earned her first Series win with a near-perfect race, coming home well clear in 1:54:26.

Following her in were two home athletes in Jessica Learmonth, who clocked 1:54:37, and Sophie Coldwell, who finished in 1:54:46, with Bermuda’s twice world and current Commonwealth champion Flora Duffy fourth in 1:55:25.