When running behind his 11th-placed teammate during the Brazilian Grand Prix, Hartley asked if he could pass with a points finish in mind– only to have his request repeatedly refused by Gasly.
"Is he gonna let me by? What the f**k is going on? He is holding me up so much," Hartley said over the team radio.
Brendon Hartley of New Zealand driving the (28) leads Pierre Gasly of France. Photo / Getty
"Mate! I'm right up his f***ing ass," he yelled. "What is happening here, guys?
"I am not attacking him, because he is supposed to be letting me by, but then he doesn't do it."
Gasly was quick to defended his actions shortly after the race and said he didn't understand why swapping the cars was necessary as both were out of the points.
But speaking to media ahead of the season finale in Abu Dhabi, Hartley fired another subtle shot at his teammate, describing the explanation as a "nice speech".
"It was a nice speech Pierre did about team orders to the media," Hartley told Motorsport.com.
"He didn't give the same one when I let him past many times, also for position, or sometimes compromised my race to help him or the team secure points.
"In the end, I was told - a long way before I caught him - that he'd let me through when I got there. And I was told each lap he was going to let me by in Turn 4.
Pierre Gasly with Brendon Hartley during previews ahead of the Formula One Grand Prix of Russia. Photo / Getty
"I did a better job managing tyres, fuel, and had better race pace than him in the race, so the team saw that I had the best chance to score points, if somebody had an issue ahead, which didn't happen."
Hartley, who faces an increasingly likely exit from Formula 1 ahead of next year's season, said Gasly's refusal to comply with the team's strategy was baffling.
"I mean, the team's position was pretty clear in the meeting so there wasn't really much more to discuss," he said.
"We have very clear team order guidelines after he went into the back of me in China earlier this season and we had the clash."
After 20 races this year, Hartley has managed just four points, to rank 19th on the ladder with his best finish a ninth placing. Meanwhile, Gasly has scored 29 points and will be joining the main Red Bull Racing team next year.
Toro Rosso bosses have since put immense pressure on the Kiwi driver, demanding a strong finish, or his place for the 2019 season will be under threat.
