With two heavy outsiders into the men’s semifinals, does the outcome of the men’s draw become a foregone conclusion? Or should momentum raise our expectations for the underdogs?
One of the most fascinating stories of the 2018 Australian Open has been the breakthroughs of a number of unlikely contenders on the men’s and women’s draws. Some of those surprises, like Tennys Sandgren and Hsieh Su-Wei, are out of the event, while others are continuing their journey. On the men’s side two unseeded players, Hyeon Chung and Kyle Edmund, have reached the semifinals, both personal bests at a Major event. On the women’s side, Elise Mertens has done the same as the only female semifinalist outside of the top 30.
For underdogs, going deep into a slam requires an incredible run. And odds would suggest that such a run is more likely to end than continue, making the chances for the pre-event favourites that much greater. But if you listen to commentary it would seem the opposite, as commentators love to back (or at least raise the odds of) the player who has the “momentum”.
So which perspective is right? Is it enough to look at who a player has won and lost to in the past to predict their future performance? Or should we consider whether a player has gotten “hot” over a short period and boost their expectations even more?
Who Has the Momentum
If we compare the Elo ratings progression among the men’s semifinalists, we can see that, if anyone has momentum going into the final days of the Australian Open, it’s Kyle Edmund and Hyeon Chung. Since the start of the year, both Chung and Edmund have gained over 100 points in their Elo rating, most of that rise coming from their gains at the Australian Open.
For Federer and Cilic, the picture is very different. They have been favourites (often heavily so) for all of their Australian Open matches so far. So while they gain with each win, the jumps are much smaller because they are playing to what was expected.
For the women’s draw, Elise Mertens is the player who most came out of nowhere, having a run that is the likes of Edmund and Chung’s.
Kerber, the only semifinalist with a Major title, also has gained a lot of momentum, making her the resurgence story at the start of 2018.
The chart above shows that player Elo ratings naturally adjust upward when players have a string of big wins, rising more steeply the more surprising each win was at the start. This is the process of trying to better align pre-match expectations with outcomes.
The question is whether, given a streak, do players gain momentum that should make us adjust their ratings even more?
Research on momentum, also called the ‘hot hand’, in sport has never had very certain conclusions. A lot of that has to do with the fact that momentum effects are difficult to measure, especially when small sample sizes are in play as with slam-specific momentum effects.
While not conclusive, it is still of historical interest to look at how other underdogs with similarly surprising runs have fared at past Majors.
The table below shows the 10 most impressive semifinalists at Grand Slams from 1990 to 2017, according to the gain in their Elo rating up until the semifinal. Only 2 of the 10 went on to win the slam, Gustavo Kuerten and Pete Sampras, first slam wins for both who would each go on to win multiple Major titles.
|Player||Year||Event||Won Title||SF Elo Gain|
|Gustavo Kuerten||1997||Roland Garros||Yes||191.4|
|Marcos Baghdatis||2006||Australian Open||No||177.7|
|Martin Verkerk||2003||Roland Garros||No||153.7|
|Jo Wilfried Tsonga||2008||Australian Open||No||135.3|
|Wayne Ferreira||1992||Australian Open||No||132.1|
|Patrick Mcenroe||1991||Australian Open||No||128.1|
|Nicolas Escude||1998||Australian Open||No||109.4|
|Filip Dewulf||1997||Roland Garros||No||108.9|
|Pete Sampras||1990||US Open||Yes||108.0|
The top 10 most surprising slam runs on the women’s side went 0 for 10 in titles. Yet, 4 of the 10 won a Major title within years of their surprise streak.
|Player||Year||Event||Won Title||SF Elo Gain|
|Clarisa Fernandez||2002||French Open||No||206.8|
|Venus Williams||1997||US Open||No||177.8|
|Amelie Mauresmo||1999||Australian Open||No||144.6|
|Mirjana Lucic Baroni||1999||Wimbledon||No||120.5|
|Kiki Bertens||2016||French Open||No||109.3|
|Angelique Kerber||2011||US Open||No||101.7|
Even those players who didn’t get the slam trophy during these runs had, by and large, great success in their careers and should be recognisable names to most tennis fans. As Edmund, Chung and Mertens have all reached the same milestone with similarly rapid gains in their ratings, they have already put themselves in an elite class of players.
Whatever happens this week in Melbourne, the forecast for their careers looks bright.