The testy relationship between leading Australian sprint cyclists Ryan Bayley and Shane Perkins boiled over when the two collided at the national track cycling championships.
Before fastest qualifier Mark French completed his domination of the sprint competition by easily beating Bayley two heats to nil in the gold medal ride-off, Bayley crashed in the third and deciding heat of his semi-final against Perkins.
Race judges relegated Perkins, meaning Bayley won the semi.
Perkins, from Victoria, strongly defended his role in the crash, stressing he did not mean for Bayley, the two-time Olympic champion from WA, to fall.
The judges also warned Bayley for "incorrect behaviour" as he reacted furiously on the side of the track after the crash.
Later in the night, Bayley needed medical attention for his injuries from the crash and it is understood he has suspected concussion.
Complicating the competitive rivalry between Perkins and Bayley is that a month ago, Perkins became engaged to Bayley's younger sister Kristine, also a former national-level track cyclist.
"The biggest thing was, I actually don't like the guy, so it made me a little bit more angry during the race and after the race," Bayley said of the semi-final.
"It's an unfortunate incident - Perkins is going really well at the moment but I don't care, because I don't like him.
"It's sprinters, we're all angry, well, according to everybody we know."
Asked about Perkins soon becoming his brother-in-law, Bayley replied: "Yeah, we won't go there.
"Ah, there's nothing I can do about it, I can just do my job and ride my bike."
Perkins said he had mis-timed his move that caused the crash "by about half an inch".
Told of Bayley's comments about him, Perkins replied: "I am engaged to his sister, which probably doesn't help things either.
"There's a bit of a personality clash - I won't say too much.
"We're professional with each other, we race against each other, for whatever reason, he's got something against me.
"He can act like a little kid as much as he likes, but we're all grown-ups here.
"I've got nothing against him at all, I don't have anything against him - you can't choose your family."
Despite their differences, Perkins and Bayley said they would be able to work with each other should they make the national team for next month's world championships and the Beijing Olympics.
Perkins qualified second-fastest, with Bayley third, in the flying 200m yesterday and there was some by-play between the two riders as the Victorian saw he had gone faster than the double Olympic champion.
As French easily beat fellow Victorian Jason Niblett 2-0 to reach tonight's final, the racing was much tighter between Bayley and Perkins - and also a lot more edgy.
Perkins went on to beat Niblett 2-0 to win the bronze medal.
While Bayley and Perkins were at loggerheads with each other, they praised the form of French, who was outstanding.
French's qualifying time of 10.099 seconds was the second-fastest seen in Australia.
"I can't take anything away from Frenchy, he rode so good today and it's actually good to see, because he really rides crap all the time," he said.
"He's always so much faster than everyone else, but he makes these massive mistakes, it's really disappointing.
"The fact that he's finally done something really quite good, when it comes to sprint tactics, it shows it might be very good for the future."