Magnussen was handed a 10-second penalty in the early laps after contact with Alex Albon, effectively ruining his own race.
However Haas was then able to use him to slow down rivals while team-mate Nico Hulkenberg – one of only four drivers who didn’t stop under the safety car – opened up a pitstop window that ultimately allowed him to secure 10th place.
What riled RB was not just the blocking tactics but the fact that having landed his first penalty Magnussen had nothing to lose. He then gained an advantage by passing Tsunoda off track, picking up a further 10-second penalty that in effect meant nothing.
“We started him on the medium tyre, and when the safety car came out, pitted him for the hard compound,” said Permane of Tsunoda’s race. “What then happened was a little difficult to take.
“Magnussen drove off the track to deliberately put himself in front of Yuki and then slowed him down by up to two seconds a lap, which allowed Hulkenberg, who hadn’t stopped yet, to create a gap and of course pit in front of all the cars behind.
“That, to me, doesn’t seem correct, and is the very definition of unsportsmanlike behaviour. I’m sure we and other teams will talk to the FIA about it for future races.”
Team principal Laurent Mekies was equally frustrated by the move.
“Yuki was fighting for what could have been a P10 finish,” said the Frenchman. “He was then passed by Magnussen, who cut the track to do so and then slowed down the whole pack to let his team-mate open a gap to pit in front of all of us.
“It made the penalty imposed on Magnussen meaningless, as it destroyed Yuki’s race."
Tsunoda admitted that he was annoyed with himself for allowing Magnussen to pass.
"It was pretty frustrating, probably my mistake was I let Kevin by,” he said when asked about his race by Motorsport.com. “But at the same time he overtook me four wheels outside.
“Okay, he got a 20-second penalty, but he was cruising around. So that felt a bit unfair, but at the same time truth is I also let him go. So that was my mistake.
“I think if I could have done a 100% job, I think I could save it and try to overtake the car in front.”
During the race Tsunoda also accused Magnussen of “dangerous driving” after the Haas squeezed him on the exit of Turn 2.
“I can understand his perspective,” he said. “He helped the team to score points, he just tried to do whatever he can do to save the position.
“He was pretty dangerous, and I almost crashed in Turn 2. I wouldn't say it was fair, but I have to understand his fight."
Asked if it was frustrating to fight a driver with nothing to lose, he admitted it was a tricky situation.
"I cannot overtake and smash the car,” he said. “The position we're fighting is always pretty difficult, but at same time these are things to be a better driver, I have to still overtake him.
“I wouldn't say it was easy, and still it was really hard to be on the track. But I think there are a lot of things at the same time where I can do a better job than that, so I have to accept it."
Regarding his drop in form in the race relative to qualifying he said: “I think a lot of things I have to improve, but at the same time the truth is also we really struggled with the pace from the beginning. I didn't have much grip, struggled to even stay in the track. So we have to look through what was going on."
