There was no way he would stop, not when he knew he was beaten by younger legs, not even when he learned on the last lap that he had been disqualified for dunking American Chase McQueen in the swimming leg some 80 minutes earlier.
Brownlee’s career has been forged on giving absolutely everything, but now – save for what even he must acknowledge would amount to a sympathy vote from the British triathlon selectors – the Olympic part of that career is over.
It is an unparalleled career in world triathlon, and one of the best in British Olympic history, but all good things must come to an end.
That it ended in Leeds, where it all began, was bittersweet. The city he calls home hosting the UK leg of the World Triathlon Championship Series for a fifth time is down to him.
Brownlee elevated triathlon into the mainstream with his gold-medal winning feats at the London and Rio Olympics, but there will not be a fourth Games.
Younger legs with fewer miles in them, fewer niggles, have brought about the end for a 33-year-old beloved by the triathlon community and his home county.
Younger legs like those of Alex Yee that took the 23-year-old Londoner – who trained with the Brownlees during his time as a student at Leeds Beckett University – to victory in yesterday’s men’s race through picturesque Roundhay Park.
Younger legs like those of Sam Dickinson, a 22-year-old from York who moved along the A64 to pursue a career in the sport because if you want to be good at triathlon in this country, you move to Leeds and get under the shadow cast by the Brownlees.
Shafts of light now puncture that shadow.
Yee must surely be a certainty to take the second spot on the plane to Tokyo, in a seat next to Jonny Brownlee, who booked a third Olympic berth late last year, and came home ninth in his home race yesterday, with no answer to the running supremacy of Yee.
British Triathlon will give themselves to the end of the month to decide who joins the younger Brownlee, with a couple of events still to be contested and no degree of certainty yet on whether they have qualified a third spot or not.
But Alistair knows his race is run.
“Over the last three months I’ve asked myself why I’m still trying to go to the Olympics and a friend pointed out ‘that’s the beauty of the Olympics’ and why I’m still here,” he said.
“I could have walked away and retired but I’m here because I love it and I want to compete, still wanted one more roll of the dice but it didn’t work out.
“It was good to finish, because I was pretty sure that was going to be my last World Series race so I had to finish.
“I always knew it was going to be a struggle, I’ve really struggled over the last three or four months with an injury.
“I needed a miracle today. I’ve done everything I can, I’ve trained as hard as I can, I’ve done all the medical treatment I could, I’ve had the best support team I could have.
“I needed a bit of luck today but I didn’t get it.”
He later tweeted: “I think GB have a great team going to the Olympics and I wish them all the best. @Lixsanyee 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.”
For the end of such a groundbreaking story over the Olympic distance, disqualification is a cruel way for the curtain to fall.
Television images showed Brownlee dunking McQueen. The open-water swim in a triathlon race is an unforgiving arena, where competitors routinely kick and knock each other to gain an advantage.
It is the general nature of the event, but the footage did not support a man who has been a byword for sportsmanlike conduct.
“I’ve seen the video since but in the middle of a swim, anything can happen,” said Brownlee immediately afterwards.
“I can guarantee just as bad happened to me 10 seconds earlier and 10 seconds later, but it’s a subjective, field-of-play decision and it is what it is.”
There were flashes of the old Brownlee. He was third out of Waterloo Lake and darted into transition, barely breaking stride as he took the saddle of his bike and powered up the hill into the lead.
For the first half of the 40km ride he was on and off the front, taking his turn to set the pace, cajoling rivals from at home and abroad to to do their bit. He bridged gaps to breakaway riders, but when Dickinson broke, so did Brownlee’s resistance and he was no longer a factor.
“He’s a double Olympic champion. We are making no decision yet,” insisted Mike Cavendish, British Triathlon’s performance director afterwards.
“We will talk to Alistair, see where his head is at.”
For his younger brother Jonny, third and second behind him in London and Rio respectively, there is work to do in preparation for the Olympic triathlon on Monday, July 26.
“It was better than Yokohama but still not great,” said Jonny, who did manage a win last week. “I didn’t feel at my best today.
“Fair play to Alex, he was sensational and this is probably the first of many wins.”
Yee was indeed sensational, and if this was the passing of the torch he was magnanimous in victory.
“Whatever happens I have so much respect for Alistair Brownlee ” said the new king.
Injuries have finally caught up with Alistair Brownlee and his rivals have overtaken him.
There were 4,000 spectators in Roundhay Park on both days to watch and compete in age-group triathlons, a para-series event on Saturday won by Lauren Steadman, and two elite races.
They were there because of the legacy built by Alistair Brownlee.
But he is now part of his sport’s past. He is no longer its present.