MONACO (Reuters) - Title-chasing Mercedes team mates Lewis Hamilton and Nico Rosberg will struggle to stay friends this season and it may not take much for the relationship to sour, according to four-times Formula One world champion Alain Prost.
While reluctant to make too many comparisons with his own past, and his famous title duels with McLaren team mate Ayrton Senna in 1988 and 1989, the Frenchman could see some similarities.
Both pairings were dominant, both fighting team mates for the crown.
"It is difficult," Prost said when asked how hard it was to stay on good terms with a team mate in such a battle.
"One little problem inside the team, or a little bit outside, and then it (the feuding) could start really very quickly," he told reporters at the Monaco Grand Prix, where he won for McLaren 30 years ago.
"It is very rare that you have a full friendship until the end. Especially if you are really fighting very hard...It looks like the team know how to approach it, but we’ll see. It also depends on the characters of the drivers."
Nicknamed 'The Professor' for his calculating and analytical approach to the sport, Prost was a very different character to Senna - much as the technically-minded Rosberg is to Hamilton, for whom Senna was a boyhood hero.
Together they dominated the 1988 championship, much as Mercedes are threatening to do with the current one, with 15 wins from 16 races.
Mercedes have won five out of five races, and started all from pole, with championship leader Hamilton chasing his fifth successive win on Sunday to stretch his three-point lead over Rosberg.
Senna won the title in 1988, although Prost actually scored more points in a season where drivers could only count their best 11 results, but Prost took the 1989 crown in highly controversial circumstances when they collided in Japan.
By then, both champions had fallen out completely.
"In 1988 with Ayrton, we had quite a good relationship. It was not a problem," recalled the Frenchman.
"It (the breakdown of relations) only started when we had the agreement in Imola and the agreement fell away. It started from this point."
At the 1989 San Marino Grand Prix, second round of the season, Senna won the re-started race with Prost second and smarting at what he felt had been a broken promise by the Brazilian.
According to the Frenchman, they had agreed that whoever was first into the first corner should be allowed to stay ahead.
Initially, that was Senna from pole. But Prost made the quicker getaway from the re-start only to see Senna - who was killed at the same circuit in an accident in 1994 - overtake him later in the lap.
"It could have been a very small detail but if you have a sort of tension, you can see something happening in the team that is a little bit different and then if you have this problem coming over the top...that could happen this year," said Prost.
"But it’s different because its Mercedes. It’s also 20 years later. And they are all talking about that so they know they are very aware of how it could (turn out)."
Hamilton, the 2008 world champion, and Rosberg have already had some stirring wheel-to-wheel duels with Bahrain in April likely to be remembered as a classic.
Teenage team mates in karting, and still solid friends when Hamilton joined Mercedes at the end of 2012, they have moved apart, without rancour, as it becomes clear that they are fighting each other for the big prize.
They now hold separate media briefings and the mind games are becoming more noticeable, with Hamilton suggesting this week that his under-privileged background made him hungrier for the title than Rosberg, who grew up in Monaco as the son of a champion.
Prost indicated he had given Mercedes, who have retired triple champion Niki Lauda as non-executive chairman, the benefit of his advice.
"I still have some people asking me what would you do," he smiled. "Which is very interesting because they ask me if I was in their position what could be the recommendation. I don’t want to tell you what I said."
(Editing by Ed Osmond)