A bit of an introduction

Fans of male tennis (organized within Association of Tennis Professionals, or ATP for short) have witnessed in the last decade-and-a-half an unprecedented domination of a small group of players, commonly named "Big Four": Roger Federer, Rafael Nadal, Novak Djokovic and Andy Murray (some people expand this group to "Big Five" by including Stan Wawrinka). Collectively, they won 46 of the last 51 Grand Slam tournaments, as well as 97 of the last 116 Masters. For over 12 years they occupy top two spots of the world rankings. Their long rule over ATP tour has been well documented. That's not what I want to focus on in this piece.

Big Four has arguably been a boon to fans but it has inhibited success of an entire next generation of tennis players, born around early 1990s. These players, the likes of Kei Nishikori (b. 1989), Milos Raonic (b. 1990) and Grigor Dimitrov (b. 1991), have become known as the "Lost generation" – a generation that for too long has been absent from lists of champions.

I began wondering. How much has this unflattering nickname been justified? How unprecedented, if at all, is this gap in successful players?

So I've gathered some data about all big tournaments after 1990 (the year modern ATP tour was established) and grouped the winners by their year of birth.

It became apparent that such visualization doesn't tell much. Sure, there is a visible uptick in 1981 (Federer) and 1987 (Djokovic and Murray) but how much of an oddity is the gap starting at 1989? After all, these players are still mostly active, and still can win trophies for their respective yearly brackets. At which point should we expect them to win more?

So I decided on a different approach. I've plotted all titles on a 2D graph, where vertical axis is a date of birth, while horizontal one represents age at the time of winning (or rather age of the eventual winner at the beginning of the tournament, as data I was working with included only start dates of tournaments; this doesn't affect the end result much – vast majority of contests are one week long, with a couple bigger ones spread over two weeks).

In this view, "real life" time runs diagonally; I've marked tour seasons with alternating stripes. In an interactive version of the graph, you can hover over any point to see tournament and winner names. This is an SVG file, so you can zoom in freely using your browser controls (usually ctrl+ and ctrl-) if you think the details are unintelligible.

So, what do we see here? There are a couple of different tournament types on ATP tour, with a varied importance, which I tried to reflect in the graph:

Grand Slam tournaments: Australian Open, French Open (aka Roland Garros), Wimbledon and US Open, are the most prestigious and some of the oldest tournaments. They all have existed for over 100 years and offer 2000 ranking points for the winner. I've marked them with big green circles.

circles. ATP Finals is a year-end tournament for eight best players of the season. It offers up to 1500 ranking points. I've marked it with medium-big azure circles.

circles. Grand Slam Cup was played throughout 1990s and was based on a similar idea: it invited a number of players most successful in preceeding year's slam tournaments. It wasn't recognized by ATP and hence didn't offer any ranking points. However, it enjoyed a fair bit of fame, so I decided to distinguish it with medium-big purple circles.

circles. There are 9 Masters tournaments each year, most of them mandatory for top players. They offer 1000 ranking points. I've marked them with medium-sized red circles.

circles. Olympic tournament happens, of course, every four years. While it currently doesn't offer any ranking, it used to be worth 750 points, and it certainly is a notable event. I've marked it with medium-small gold medals (actually orange, for better visibility).

(actually orange, for better visibility). And finally, there is a myriad of base-level tournaments throughout the season. They offer 500 or 250 points each. I've marked them with little grey dots.

I will be talking a lot about "large tournaments". By that I will mean any tournament other than 500- or 250-level, so any dot other than little grey ones.

When reading my takeaways, please note that I cannot be called tennis expert by any stretch of imagination. My conclusions are based largely on raw data and may lack some important context of the time.

Lost generation?

One thing is apparent from this graph: the lost generation is real. There is a huge, unprecedented hole in large tournaments wins after 1988 and even small tournaments wins are significantly less frequent for some time. There are only five titles won in the highlighted region:

By comparison, here's the same region 10 years earlier:

1977-79 were the last time players of three consecutive birth years failed to win any large tournament before turning 23. This time the span is already twice as long (1989-94) and it may even expand to 8 years, if Kyrgios fails to one-up his game quickly (there are only 4 large tournaments left before he turns 23).

With lost generation members Dimitrov and Sock, as well as newcomer Alex Zverev, all winning their maiden Masters titles in 2017, certainly some wind of change can be felt. It remains to be seen how steadily it will blow.

Side note: Tour finals are currently underway, and all remaining contestants, except Federer, are members of lost generation (one can argue that Dominic Thiem is too young to deserve that label but let's face it – if history is any indication, when you are 24 and without a large trophy, either A) you won't be one of the greats or B) hello, Mr. Wawrinka, that's really nice to meet you!). Just one more clue that times are a-changing.

A case for Zverev

Speaking of Zverev the younger, he is leading the charge of newcomers on the tour. With two Masters titles this year, he is already the most successful player since 9 years older Marin Cilic. At about 20.5 years of age, what can we say about his prospects? It's tough to come with clear predictions, as precedents are all over the place.

At this point in life, Novak Djokovic also had two Masters titles. Now he sits on 12 Grand Slam, 5 ATP finals and 30 Masters titles.

On the other hand, Andrei Medvedev won two Masters titles before turning 20. He retired with "only" four Masters titles and without capturing a single Grand Slam trophy. Michael Chang was even more successful in early years, winning third Masters title soon after turning 20. He also failed to win at Grand Slam. Correction: Chang won French Open in 1989, before ATP Tour was established.

Correction: Chang won French Open in 1989, before ATP Tour was established. Conversely, Rafael Nadal accumulated 2 Grand Slam and 6 Masters titles by that age. But Roger Federer hadn't captured any large trophy yet.

30+ year olds are like fine wine…

… Who wouldn't want a fancy dinner with one? Also, they just get better and better. Just look at what happens after turning 31 now and in the past. Back then there was Agassi, still winning large tournaments at 32 (and even one at 34), and Sampras with lonely US Open win just after he turned 31. And that's pretty much it. Even smaller titles were won sporadically at that age in the good old days.

Now we have Federer, Wawrinka and Nadal all winning large tournaments after turning 31, and a whole host of other players – like Mahut, Ferrer or Tsonga, to name just a few – grabbing smaller trophies way into their thirties.

It looks like the trend started with players born in 1981 – Hewitt, Federer and Feliciano Lopez specifically – although there were some earlier signs of things to come with Estrella (b. 1980, still winning at 36), Karlovic (b. 1979, adding two titles to his collection at 37) and Haas (b. 1978, grabbing two trophies at 35).

The lost generation might be struggling to earn their place in tennis history books for now but if the longevity trend is going to continue, they still have a decade or so to develop their careers.

The (seemingly) never-ending stories

The clearly distinguishable horizontal patterns that some dots form on the graph are usually a result of multiple trophies won by a single player. And some of the patterns are impressively wide.

Andre Agassi won his first large tournament at 1990's Miami Masters. Within the following year, John McEnroe managed to clinch his last two victories before retiring. Agassi earned his last large title at 2004 Cincinnati Masters, just a week apart from Rafael Nadal's first trophy. McEnroe was born in early 1959, Nadal in 1986, and they both were Agassi's contemporaries on the tour.

One of his other contemporaries, Roger Federer, claimed his first victory in early 2001 in Milan, some month before Francisco Clavet's final title. Federer's last victory so far came in late 2017 in Basel, a few months after Alex Zverev conquered Montreal. Clavet was born in 1968, Zverev in 1997, and again: both were/are Federer's contemporaries.

Interweaving success stories

I've mentioned above that horizontal patterns are usually painted by a single person. That's not always the case. Sometimes two or more successful players are born within weeks of each other and their respective careers blend in the graph.

Pete Sampras was born on 1971-08-12. Before Federer's rise he was often considered the greatest male tennis player of all time, winning 64 titles, including 14 Grand Slam trophies and 5 year-end championships. Goran Ivanisevic was born a month later, on 1971-09-13. He won 22 titles, including Wimbledon in 2001. Wayne Ferreira was born just two days after Ivanisevic, on 1971-09-15. He won 15 titles, including 1996 Canada Masters and 2000 Stuttgart Masters.

Carlos Moya was born on 1976-08-27. He won 20 titles, including French Open in 1998. Gustavo Kuerten was born two weeks later, on 1976-09-10. He also won 20 titles, including French Open in 1997, 2000 and 2001, as well as Masters Cup in 2000.

Marat Safin was born on 1980-01-27. He won 15 titles, including 2000 US Open and 2005 Australian Open. Juan Carlos Ferrero was born two weeks later, on 1980-02-12. He won 16 titles, including French Open in 2003.

Andy Murray was born on 1987-05-15. He won 45 titles, including 3 Grand Slam trophies, tour finals and 2 Olympic gold medals. Novak Djokovic was born exactly a week later, on 1987-05-22. He won 68 titles, including 12 Grand Slam trophies and 5 tour finals.

Juan Martin del Potro was born on 1988-09-23. He won 20 titles, including 2009 US Open. Marin Cilic was born just 5 days later, on 1988-09-28. He won 17 titles, including 2014 US Open.

Battle of generations

Following the diagonal stripes, we can explore the age variance of winners within a single season. And there are huge differences in that context across the years.

In the very first edition of ATP tour, 1990, French Open was won by 30-years-old Andres Gomez. 11 years younger Pete Sampras captured US Open the same year. In 2003 Andre Agassi, then 32, became Australian Open champion. Later that year his compatriot, 20-years-old Andy Roddick, won US Open. In both cases there was over a decade difference between youngest and oldest Slam champions that year.

In 2013 all Grand Slam tournaments were won by three players born within a year of each other: Novak Djokovic (Australian Open), Rafael Nadal (French Open and US Open) and Andy Murray (Wimbledon).

The same situation happened in 2011 as well, this time all trophies were shared between just Djokovic and Nadal.

In 2014 all Grand Slam tournaments were won by players of four consecutive year-groups: 1985-born Wawrinka won Australian, 1986-born Nadal captured French, 1987-born Djokovic claimed Wimbledon and 1988-born Cilic triumphed at US Open.

Some anachronisms

Looking at the data in the form of colorful dots, I've noticed a couple of things that were unexpected for me but perhaps rather obvious for someone more closely following the sport.

Watching Federer's rise to fame in 2003, then arrival of Nadal in 2005 and finally Djokovic and Murray in 2008, I've always had an impression that Nadal is about halfway between Federer and the other two, age-wise. Not at all, he is much closer to Djokovic and Murray, and the false impression is largely due to Nadal's incredibly quick rise and Federer being a relative late-bloomer.

Also because of Federer's longer than usual incubation period, I didn't expect him being Hewitt's peer. Hewitt won his sixth and final large tournament before Federer captured his first Grand Slam trophy. This didn't prevent Hewitt from semi-regularly winning smaller titles for the next 11 years.

To conclude

Okay, that's enough trivia for one time. I believe this presentation of data (age and date of birth at two axes) can shed a new light on some aspects of the sport's history. What story can you read from the graph?