Mexico City ePrix runner-up Jean-Eric Vergne slammed Jerome d'Ambrosio's "totally stupid" defensive driving for costing him a shot at a first Formula E victory.
Techeetah driver Vergne ran third in the latter stages of Saturday's race, but had a superior energy supply compared to second-place driver d'Ambrosio and race leader Lucas di Grassi, who had both stopped early.
But while di Grassi escaped at the front, Vergne found himself unable to clear Future Faraday Dragon driver d'Ambrosio, who defended stoutly as he tried desperately to save energy.
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Verge ultimately found a way through with three laps to go, but by that point was too far behind di Grassi to challenge for victory and instead had to settle for second.
Speaking after the race, Vergne hit out at d'Ambrosio's tactics - suggesting the Belgian had crossed a line during their battle.
"It was the manner in which he [d'Ambrosio] defended today which I find unacceptable and unfair," Vergne told Autosport.
"He pushed me off the track many times while I was trying to overtake him and he was never going to finish the race anyway with his energy levels. It was totally stupid.
"In the end it cost him his race and it cost me a chance to win so I have to wonder if the guy has a brain.
"He wanted to speak to me afterwards but I've nothing to say to him.
"The pictures do the talking. I don't think we would speak the same language on these tactics anyway."
D'Ambrosio argued he had been fair in his defence of the position, despite the discrepancy in remaining useable energy between the two cars late on.
"I was doing my race and if he [Vergne] is expecting some people to give way to him then this is not racing is it?" said d'Ambrosio, who was ultimately classified 14th.
"If the FIA think I was too aggressive and not driving within the rules then they will let me know and I'll get a warning, I'm sure.
"From my point of view I turned in early, didn't move in my line.
"I didn't give much space but this is racing.
"I understand it can be frustrating but everyone is doing their own race and it's what the fans want to see I think."
VERGNE TARGETS E.DAMS
Despite his frustration, Vergne said the Mexico result - his second podium in as many races - gave him confidence that he and Techeetah could challenge the dominant Renault e.dams team.
"It is encouraging because we showed today that we could beat the works team [Renault edams]," he added.
"They are not unbeatable and this makes us hungrier for the future.
"We are in the championship and have taken 17 points out of Buemi today.
"If we can do this and put more pressure on them then who knows what can happen."