Espargaro was in the fight for a top-five position when his RS-GP suddenly slowed on lap eight of Saturday’s 12-lap race, won by Jorge Martin's Pramac Ducati, forcing him into the pits and retirement.

It follows a similar episode in last weekend’s Indian Grand Prix but, while Espargaro put that problem down to the intense heat at the Buddh International Circuit, this time he was a lot a loss to explain what caused the issue.

“I don't understand what's going on; the problems of the past are coming back,” a visibly frustrated Espargaro told reporters after the race. “I don't really know what to say. 

“In Buddh one part of the bike was damaged in qualifying, and another in the race. Today, it happened again. 

“I think when it comes to the races I'm proving to be very competitive. This time I was [fighting for] fifth again, riding very fast. 

“I can't do any more, and this would take away the enthusiasm and the desire from anyone. Right now I would choose to go home.

“One of the cylinder banks of the engine stopped, and the bike wouldn't go over 80km/h. This time, unlike Buddh, the engine has been damaged and we have to change it. 

“It's true that we have problems when it's very hot, but I don't think this was the problem, because the temperature here is not like it was in India.”

After emerging as a title contender with Aprilia for the first time last year, Espargaro suffered a notable drop-off in form towards the end of the year, failing to finish in the top eight in the final five races of the season.

That included a bike problem that forced him to start from the pits at Motegi last year, and another problem in the Valencia finale that forced him to retire.

“It always happens in the second half of the championship, not in the first half,” pointed out Espargaro. 

“The engineers may think it's a matter of bad luck because it's a small part like this. But I don't believe in bad luck, so it should be investigated.”

After Espargaro’s exit, Aprilia came away with a single point from the sprint as Maverick Vinales came home ninth, with Raul Fernandez completing the top 10 on his RNF-run satellite RS-GP.