The US Open Tennis final is contested by a set of new young tennis players, who appear to be finally unseating the 'old guard', including Roger Federer and Novak Djokovic. This is how a series of remarkable upsets at the very top of the game, is being portrayed in the press.
But there is a new theory in psychology which explains the current spate of early tournament reversals suffered by these normally unbeatable players.
Speculation over Roger Federer's retirement has gathered pace since two sets of twins arrived in his marriage, but while Novak Djokovic is six years younger than Roger Federer at 27, he is newly married and expecting his first child shortly.
Could this be the key link between these two giants of the game, who both almost simultaneously suffered unexpected defeats?
This may seem fanciful, but a study entitled 'Marriage affects competitive performance in male tennis players', by psychologists Daniel Farrelly and Daniel Nettle, found that professional male tennis players perform significantly worse in the year after their marriage, compared to the year before, whereas there is no such effect for unmarried players of the same age.
It is notable that both finalists in the US Tennis Open, Marin Cilic and Kei Nishikori, do not appear to be married, in contrast to the players they defeated.
Is it also a coincidence that Rory Mcllroy, one of the world's top golfers, seems to have overcome a period of relative under-performance, stringing together a series of recent victories, shortly after, it appears, breaking up with long-standing girlfriend, Caroline Wozniacki?
She had been reported to have been 'dumped' by Mcllroy shortly after they sent out wedding invites. But, according to the latest psychological research, Rory Mcllroy made the right move if staying at the top of golf was his key aim. His sporting prowess since the break-up would appear to bear that out.
The authors of the study, published in the 'Journal of Evolutionary Psychology', suggest that following marriage, men experience a psychological mechanism which has evolved over many generations from our ancient past, and which inevitably leads to less motivation to engage in competition.
Daniel Farrelly and Daniel Nettle investigated male tennis players who had appeared in the top 100 players in the ATP singles rankings at the end of each year, from 1995 to 2005.
Their investigation found married players suffered a significant decrease in ranking points between the year before getting married, and the year after, whereas there was no such difference in performance for unmarried players, during the corresponding time period.
Married players also suffered a significant decrease in winning percentages between the corresponding years, whereas there was no such difference in performance for unmarried players.
But married players may not be suffering decreased competitive drive, but merely less ability to commit to tournaments around the world? The authors of this study, based at the University of Worcester and the University of Newcastle, argue that their results indicate this does not seem to be the case. Success in actually winning matches significantly decreased following marriage.
This is possibly produced by reductions in the levels of hormone Testosterone, which men experience as a result of marriage. Testosterone is found in much higher levels in men compared to women, and is associated with aggression, competitiveness, dominance and risk-taking. Testosterone is thought to be important in winning in sports and other adversarial encounters between men.
Psychologists argue that men compete in sports, and other activities (practically anything in fact), to become 'top dog', as this then makes them more attractive to the opposite sex.
This need to beat others is therefore an evolved motivation in male psychology. It could be said to be genetically wired into the male brain. In ancient times moving up the hierarchy of the tribe was a sexual strategy for men. Being seen as superior in physical and mental prowess, gains greater opportunities to mate with more desirable women, through increased status, according to this theory.
Competing successfully in adversarial encounters with other men, in our ancestral environments, led to maximising male reproductive success - passing on more genes to future generations.
Other research, in support of this theory, has shown that when a male's mating strategy shifts from acquiring mates to maintaining them (i.e. following marriage), his Testosterone levels drop. This has been shown among married men, and those in long-term committed relationships (Rory take note).
Following marriage, however, (according to this theory) men devote their resources to looking after their partner, and so divert energy away from beating male competition. Marriage, according to these evolutionary arguments, inevitably means men lose their edge when competing.
From an evolutionary standpoint, men need to protect their genetic legacy, and this is best achieved after marriage, by looking out for their family, rather than continuing to compete with other men, so running the risk of neglecting their partner or children.
Indeed should they continue to challenge other men outside the family home, then the neglected partner left back at the cave, might become contested for by another male.
According to this evolutionary theory, men compete to rise up any ladder, tennis rankings, or anything else (it doesn't actually matter what), because, fundamentally, they are really trying to get hooked up.
Theoretically, this process is operating at an unconscious level, so Djokovic and Federer may themselves remain unaware of why their performance was below par, and neither may Rory be fully aware of precisely why his game picked up either.
It remains to be seen whether sports psychologists start advocating separation as a way of rescuing your career, but we do know Testosterone levels go back up after divorce.