Alain Prost and Ayrton Senna became teammates at McLaren in 1988. The Frenchman joined the Woking outfit in 1984, as teammate to Niki Lauda. After losing out by half a point that year, he came back to clinch back to back championships in the following two seasons. After a difficult 1987 campaign, 1988 was a season of changes at McLaren. Honda, which conquered F1 with Williams in 1987, left the squad of Grove and joined McLaren.

There was also a change in the line-up to be made, with an open slot next to Prost. The primary contenders were two Brazilians: Nelson Piquet and Ayrton Senna. After lengthy discussions with both, Ron Dennis took the advice of Prost and hired Senna, with a view to the future.

Having built a beast, the all-conquering MP4/4, the fight for the title was between the two teammates. Their first big battle did not even involve wheel-to-wheel racing. In fact, far from it. In a famous qualifying session, Senna demolished the opposition and took a dominant pole position, 1.4 seconds ahead of Prost and 2.7 ahead of third-placed Gerhard Berger.

At the start, Berger got the better of Prost to climb up to second. While the polesitter pulled away, his teammate was stuck behind the slower Ferrari. It took the Frenchman 54 laps to get in front of the Austrian, by which point Senna was 50 seconds up the road. With only 24 laps remaining, there was no battle for the lead. Or so we thought, before Prost used some brilliant mind games. Jo Ramirez was the team coordinator of McLaren and talked about that race to Malcolm Folley for the book “Prost vs Senna”:

“Alain got rid of Gerhard and started getting faster and faster and record lap after record lap. He was gaining seconds every lap. Of course Ayrton sees that and Ron was shouting at him “He is never going to catch you, no way, it’s 50 seconds you are in front. Slow down, slow down, concentrate.” He just wouldn’t hear it, Prost was behind so he had to get quicker and quicker. He missed the corner, hit the guardrail on the inside and went on the other side and that was it, his race was finished.”

Senna was distraught after the crash at Portier. He went straight to his hotel and did not talk to anyone for several hours. Prost took over at the front, scored his third of seven victories in 1988 and extended his championship lead.

Despite a close fight for the rest of the season, the relationship between them was okay. However, there were two noteworthy incidents that set up the stage ahead of 1989.

The first was in Italy, when second-placed Alain Prost suffered from a misfiring engine. Suspecting that he would not make it to the finish and desperate to keep his championship chances alive, he turned up the turbo boost of his engine, hoping to get Senna to push too hard and compromise his race. Prost retired on lap 34 of 51 and Senna backed off, reportedly needing to save fuel. The Ferraris of Gerhard Berger and Michele Alboreto were catching him at a rate of knots. At the end, it did not matter, as Senna collided with the lapped Williams of Jean-Louis Schlesser with a couple of laps remaining. The Brazilian’s subsequent retirement meant that McLaren lost for the first and only time in 1988, as Gerhard Berger picked up the victory for Ferrari.

The second incident was in Portugal, where Prost achieved only his second pole position of the season. At the start, Senna took the lead and his teammate followed closely. Through the start-finish straight, at the beginning of the second lap, Prost made his move to take the lead back. He pulled out of the slipstream, but Senna defended aggressively. He squeezed Prost to the pitwall, but the Frenchman did not yield. He kept his foot in the throttle and took the lead back. Senna dropped back because of issues with fuel readout and Prost went untroubled on his way to victory, but he was still livid with the Brazilian’s defence. Here is a video of the overtake:

As Jo Ramirez recalls, this is what the Frenchman told his teammate following the Grand Prix: “You are crazy! If the championship is so important to you that you are willing to kill or be killed, it’s yours. I don’t want to be part of it. I enjoy my life and I want to keep on enjoying it.”

The championship ended with Senna on top, for his first World Championship. For Prost, the winter break was not good. Because of a change in the regulations, McLaren and Honda had to move away from their turbocharged V6 engine and developed a V10. A lot of testing had to take place, but Senna was nowhere to be seen, enjoying his holidays in Brazil, with Prost commenting on the situation:

It was tough, I’d had two weeks holiday and he was doing nothing for three months. I felt like we had different jobs.

McLaren organized a five-day test at Rio de Janeiro, with its two drivers splitting duties. However, things did not go as planned, as Prost described to Folley:

“Ayrton started the test. But after half a day in the car he said to Ron that he didn’t want to test any more, because he said that I was so much better than him at setting up the car. Ron came to me and said, “Please, can you do the test.” I was stupid enough to do the test – but after I had the car how he wanted, Ayrton came back towards the end and said he wanted to drive again. So he did. That was not correct.”

The start of 1989 showed that things were harder than the previous season. Although the Ferrari car was unreliable during testing, it unexpectedly lasted the whole race at the season opener in Brazil and Nigel Mansell was the winner. To protect a good result for McLaren, its two drivers made an agreement ahead of the following event, at Imola. And that’s when it all came to a head.

Here is what Prost had to say about what happened that day:

“Ayrton had pole and I was second. But we were not confident about the start, so we agreed we would not race one another until after the first corner, Tosa. It was Ayrton’s idea. We had this agreement two or three times and it always worked. At the start, Senna got away first and I let him go. Then, Berger had his accident and the race was stopped.“

The accident Prost is talking about happened at the start of the fourth lap. Something failed on the Ferrari of Berger and he went straight off at Tamburello. Despite a monstrous impact, which knocked him unconscious, and a subsequent fire, the Austrian was miraculously saved and only suffered broken ribs, along with second-degree burns.

After a lengthy stoppage, the race continued. As the rules stated at the time, the restart took place with a standing start. Now, back to Prost, who believed that the agreement with Senna was in effect for the second start as well:

“This time I started better than Ayrton. I looked in my mirrors and saw it was him closest behind. We were first and second, and I felt there was no risk to have another accident. For me, the race was going to start after the corner. I preferred to take the average best line through this corner, again because there was no need to take a risk, and then boom, Senna was inside me.“

Here is a video of the significant, as it proved to be, overtake:

Senna was into the lead. A livid Prost was in second position, but his anger got the better of him. He was unable to chase the other McLaren and even made a couple of uncharacteristic mistakes. The order stayed like that until the finish.

Senna offered his explanation a few days after the incident, talking to the French newspaper “L’ Equipe”:

“Last year, he had suggested that we should not attack each other on the first bend of a Grand Prix. It was his idea. I had never found myself in this kind of situation before and I said OK. We respected this agreement for several races. Then, as our relationship deteriorated, we stopped doing so. This year, after the winter break, we were on more friendly terms. Then came Imola.”

“I remembered the agreement of the previous year. And I put the question to myself: what shall we do about the first bend? He replied to me: the same as ’88. So that was the situation. On the first start, there was no problem. I was in front. On the second, after Berger’s accident, he got off to a better start than me. But I got in his slipstream and accelerated quickly. I was going faster than him. I then started the maneuver to overtake him. Not at the first corner, before that. It was when we were braking that we were not to attack each other. We had a momentary confrontation and then I drove clear. He made a mistake and skidded off the track. He had made a driving mistake, but he was trying to make me take the blame.”

“The original idea was simple: No overtaking as we braked on the first bend. After the race, I had a clear conscience. I didn’t think the whole thing would take on such proportions.”

The next dramatic chapter in the history between the two drivers played out two days after the race. McLaren was testing at Pembrey, in South Wales, ahead of the race in Monaco. Both drivers were there, as well as Ron Dennis, who usually did not attend tests, but did so on this occasion. The reason was a meeting between the three, to clear the air after what happened at Imola.

Prost talked to Folley about the infamous meeting:

“Ron started to talk. He said to Ayrton we have to fix the problem we had on Sunday. He asked him: “Is it true you had an agreement?” Ayrton said, “Yes.” Ron then asked him: “Why did you not honor it?” Ayrton said: “It’s not me – it’s Alain that broke the agreement.” This was absolutely unbelievable. Ayrton offered all kinds of excuses. He said the agreement was for the first start, not the second. Ron was not taken in by this. Then we had a good twenty minutes, maybe half an hour discussion. I was hardly talking except to say this was not good for the spirit of the team, that the team was starting to break up. Then Ayrton started to cry, started to cry. That is the truth. It is difficult to understand why, again because he is different. He has lied. When he said to me, “You broke the agreement”, he was convinced he was right. I said, “Ayrton, you were there”. Maybe he cried because he realized he was wrong and lost his honor.”

At this point, you might think that things could not possibly get worse. In which case, you would be wrong. In the days following what happened at Pembrey, Prost was called by a friend of his, who worked for L’Equipe and was asked to comment on what happened in the meeting. Prost told he could not explain everything, but he would tell a few details off the record. However, those details ended up getting published. Word got to Senna’s ear and that was the final straw. The war between Alain Prost and Ayrton Senna was declared.