The most famous F1 teammate rivalry, that of Ayrton Senna and Alain Prost, took a while to bubble up after an amicable start at McLaren.
While now well known as the best example of how competitive teammates can turn bitter and ruthless towards each other in their quests for individual glory, the start of Ayrton Senna and Alain Prost's relationship at the dominant McLaren team in 1988 actually proved quite straightforward.
But, as the races ticked by, it seemed inevitable that, at some point, the two highly competitive drivers would develop a more strained dynamic, and McLaren's Neil Oatley suspects two incidents in particular set off the domino effect that led to the all-out war that developed between Senna and Prost in their title deciders at Suzuka in 1989 and '90.
"It was good. I mean, there wasn't really a lot of tension, particularly in '88," Oatley, Prost's race engineer at McLaren that year, told the Beyond the Grid podcast about the first few months of Senna and Prost's relationship.
"It was a fairly friendly atmosphere. I'd worked with Alain the previous year on the MP4/3 and, literally, the first time I ever met Alain was actually for the Brazilian Grand Prix that year. The flight was delayed going out there so we didn't arrive until Thursday night, so the first time I met him was just before first practice!"
The first signs of malcontent between the two drivers came at the 1988 Portuguese Grand Prix, as the pair took swipes at each other - Prost taking a more subtle mind-game approach to annoying Senna, with Senna responding by using his car to show aggression to his teammate.
Prost had taken pole position by almost half a second over Senna on the Saturday, but set about winding Senna up by sitting out half the session - a pointed move clearly seen as antagonistic by the Brazilian.
"[Alain] was really quick," Oatley said.
"Literally, I think half an hour into the session, he went off to the truck, got changed into his civvies, and just leaned on the pitwall looking into Ayrton's garage. I think Ayrton just wanted to touch his nose after that!"
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On race day, Senna managed to get the jump on Prost to take the lead but was powerless to stop the French driver from overtaking him down the pit straight. During the move, Senna crowded Prost over close to the pitwall, clearly showing more aggression than perhaps may have been expected by McLaren.
Oatley has a gut feeling as to why there was such a disparity in pace that day.
"On his day, Alain could be very, very quick," he said.
"But I think also Ayrton had a slight problem with his engine settings, so there may have been a slight detriment to the performance of Ayrton's car, which helped, because there was a reasonable difference in Jerez as well, but nothing like as it was in Portugal.
"I think it was [the first moment of tension], to be honest - it may have been partly as a result of what Alain did the previous afternoon. I think it had been a fairly amicable year up to that point, but then that did create a little bit of tension, which also then bubbled over six months later at Imola."
McLaren's dominance was still on full display at the 1989 San Marino Grand Prix at Imola, with Senna heading to the race as defending World Champion after beating Prost to the '88 title.
After a horrible crash for Gerhard Berger in the early laps, the race was restarted, with Prost overtaking Senna off the line to lead into Tamburello. But Senna got back ahead into Tosa, and set about establishing a lead and winning the race.
Prost was furious afterward, revealing that an agreement had been put in place that whoever led into Turn 1 could win the race - an agreement he felt Senna had ignored.
"Obviously, it changed slightly after Imola in '89," Oatley said of the weekend that turned the relationship sour.
The engineer revealed that, from then on, the drivers would take pains to ensure they didn't engage each other in conversation, even at the debriefs!
"We'd be sitting around the table, both drivers, myself, [and all the engineers]," he said.
"But the drivers would never speak to each other. If Alain wanted to know something about Ayrton's car, he'd ask Steve [Hallam, Senna's race engineer], and if Ayrton wanted to know something, he'd ask me and not Alain. So it was a slightly strange situation, but not really any animosity in that situation."
Despite their animosity, Oatley explained that the two drivers didn't set out to cause each other problems in terms of setting up their cars.
"It was actually fairly open. I think that the setups didn't really vary very much, because they only really had to worry about the guy on the other side of the table," he said.
"So it was fairly open and there wasn't really anything underhand.
"The two drivers setups rarely deviated from one another, because then it's basically fair. If they took a different direction on setup and actually made it worse, then the other guy would get an advantage. So they both were just tweaking little things on set up, no big changes. All they were doing was looking across the garage at what the other guy was doing."
As for Ron Dennis, Oatley said the McLaren team boss did a great job keeping the animosity from affecting the dynamic of employees working within the organisation.
"I think that was a major part of his working day - pacifying and keeping both happy and performing well," he laughed.
"It was something he sheltered the rest of the team from very well, in fact, and so we weren't really that bothered but, obviously, it did get a little bit more tense in '89. I think, from Imola onwards, the drivers just didn't speak to each other."
With Prost winning the '89 title and leaving for Ferrari, only for their bitter rivalry to continue in 1990, Oatley was asked whether Prost ever suspected that Senna had the edge on him in terms of outright speed.
"I never asked him that question," he said.
"I think my gut feeling is yes, but it didn't really bother him. Obviously, they were half a generation apart. So Alain had done his bit, and was a lot further in his career. Ayrton wanted proof that he was the fastest driver ever, but it's not something that really played on Alain's mind."