The one person in F1 that Max Verstappen actually listens to

Or nearly alone.

For the next two hours, Verstappen navigates the pressure cooker of a Grand Prix with nothing but his instincts, his reflexes, his explosive temper—and the soothing tones of a measured British accent in his ear.

The voice, broadcast directly to Verstappen’s helmet and bumping up against his own thoughts, belongs to Gianpiero Lambiase. He is the British-Italian engineer who has sat on the pit wall, on the other end of Verstappen’s radio, coaching and cajoling one of motor racing’s most temperamental geniuses. They’ve spent nearly 100 days a year together for almost a decade, through foul-mouthed rants and four world championships. One former boss compared them to “an old married couple."

But in Verstappen’s one-man cockpit, Lambiase is actually closer to a co-pilot.

“Both of us have quite fiery characters, and I think that’s good," Verstappen says. “I wouldn’t want it any other way, honestly."

From the pit wall, any number of Red Bull team officials can radio into Verstappen, including the team principal. When Verstappen pushes his button to talk, however, the only person he can reach is Lambiase—which isn’t to say the conversations are private. In recent years, Formula One has made all race radio available to every team, allowing rivals to listen in, and snipped the juiciest exchanges to be aired on the live broadcast.

So everyone in F1 has heard Lambiase be insulted, cursed at, adored, and praised by the Dutchman at the wheel. Even Verstappen occasionally reminds himself that he and the man he calls GP aren’t on a secure line.

“You remember GP has a family as well, so they are watching," he says. “If you are, you know, shouting on the radio, that is not always a nice thing for them to see."

That doesn’t always stop him. Verstappen, 27, was one of the primary targets of motor racing officials’ efforts last year to curb the use of profanity over the radio. In Singapore, he was ordered to “accomplish some work of public interest" for his inappropriate language during a news conference.

But in the heat of the moment, at 200 miles per hour, the odd radio F-bomb is an occupational hazard. Lambiase knows enough not to take them personally.

“Mate, this car is just undrivable," Verstappen fumed during the British Grand Prix this summer. “F—!"

Lambiase, 44, is the only race engineer Verstappen has ever known at Red Bull, the team he joined at the age of 18. And, initially, the University College London-educated mechanical engineer felt intimidated. He’d been entrusted with the care of F1’s newest wunderkind, a driver destined for world titles from the moment he first zipped up his overalls.

If they couldn’t forge a good working relationship, then Lambiase had no doubts that his career as a Red Bull race engineer would be a short one. Nine years later, Lambiase now feels that his job every Grand Prix weekend is to be Verstappen’s “dad, a sports psychologist, best friend, worst enemy, everything," he says. “You’re his complete circle of friends in one."

He is also Verstappen’s eyes for everything beyond the narrow letterbox of his helmet. Lambiase fills in the picture with news of weather, track position, and the competition. The important thing is to pick his spots, because Verstappen won’t be shy about telling the pitwall to zip it—just like the time in Austin that Lambiase kept babbling to Verstappen in high-G-force braking zones.

The engineering part comes in when Lambiase is helping to devise strategy and the constant barrage coming at him from around 16 radio channels connected to every department—chassis performance, aero control systems, tire monitoring. On the pit wall with his nose glued to a bank of monitors, he sometimes looks like he’s running an Apollo lunar mission.

They are the highest-performing race cars in the world. Each one is its own miracle of engineering. But equally, a million things are always going wrong. Lambiase can see the problems bubbling up in the data and Verstappen can feel them encased in the cockpit. What sets Verstappen apart is how effectively he can translate a vibration in his wrists or the texture of his brakes into usable data.

Then it’s up to the guys wearing headsets to survey the state of the race and decide what constitutes an emergency.

“You’re on a boat down a river, and you’re surrounded by a whole load of crocodiles," Lambiase says. “So you’re dealing with the closest crocodile to the boat. That’s all we’re doing.

Sometimes, though, the crocodiles are coming from inside the boat. That was the case in Hungary last year—and it sent Max-GP relations to their lowest point.

The problem was a disagreement over pit-stop strategy, which Verstappen felt cost him vital track position. In no uncertain terms, he let Lambiase know that he blamed him for his race going down the tubes.

“You guys gave me this f—ing strategy, OK?" Verstappen said. “I’m trying to rescue what’s left."

The pair didn’t speak for three or four days after that. By the time they had cooled off, Verstappen and Lambiase were able to clear the air and get back to work. It wasn’t their first disagreement, and they knew it would be far from their last. Lambiase admits that he gets carried away, too. Instead of talking Verstappen off the ledge, he needles him a little more. And like anyone in a long-term relationship, he can detect a change of mood in the cadence of his voice.

What makes this one work is their understanding that mildness doesn’t win F1 championships.

“He’s very straightforward, blunt and honest, but he expects that similar level of treatment back," Lambiase says. “If you try to pander to him—wrap him in cotton wool and try to be his best mate and be that yes-man—you will lose him within months

He can’t pander to the cameras either. Millions may be eavesdropping, but wherever they are, however fast Max is going, Lambiase and Verstappen have no time for anything more than clear, direct, us-against-the-world conversation.

“You have to do what is right for the team and driver at the time," Lambiase says. “And if you start being concerned about what you’re saying, then I think you’re lost in showbiz."

Write to Joshua Robinson at Joshua.Robinson@wsj.com