ABOUT THE AUTHOR: MARTIN INGRAM – DATA SCIENTIST

Martin is passionate about good code and gaining insights from data with a particular interest in sports analytics. He completed a Bachelor Of Arts, Natural Sciences (Physical) at Cambridge before completing his Masters of Science, Computing Science.


In this preview, I use Glicko, a ratings system developed by Harvard Professor Mark Glickman, to predict this year’s Wimbledon tournament. Glicko is a generalisation of the Elo rating system which considers not just a player’s mean skill, but also the uncertainty about that skill. This allows Glicko to deal more naturally with player absences: if a player is out of the competition for long periods, Glicko becomes more uncertain and makes larger adjustments to their rating when they return, allowing it to adjust to injuries more quickly than Elo.

Players’ skills can vary a great deal by surface. To deal with this, I compute a weighted average of players’ Glicko ratings on grass with the overall ratings, which gives them more credit for strong showings on grass than Glicko normally would.


PlayerSkillUncertainty
Roger Federer206775
Novak Djokovic199577
Andy Murray*198992
Rafael Nadal189666
Milos Raonic183667
Kei Nishikori183568
Marin Cilic182662
Juan Martin Del Potro182163

On the men’s side, the favourite for the title is eight-time winner and defending champion Roger Federer with 2067 points. Like last year, he skipped the clay season but returned to play on the grass courts in Stuttgart – which he won – and Halle, where he reached the final but lost, surprisingly, to Borna Coric.

Glicko has Novak Djokovic not too far behind Federer, at 1995 points. Djokovic has had a difficult time since 2016, winning no majors since the French Open that year. His recent form seems to have been improving, however. He reached the quarter final at the French Open and the final of Queen’s, where he lost a close match to Marin Cilic, last year’s Wimbledon finalist, suggesting that he may be in good shape for Wimbledon.

The third favourite is Andy Murray, but I have placed an asterisk by his name. This is because although he has historically been very strong on grass, Murray is returning from an injury break that lasted almost a whole year. If he is physically fit, he can be a threat, but that remains to be seen. The doubts about his form are reflected in Glicko’s uncertainty estimate: at 92, he has the highest uncertainty of all players in the top 8.

It may be surprising to see Rafael Nadal, who just won the French Open after a dominant clay season, coming in with a gap of around 170 points behind Roger Federer. However, Nadal has struggled on grass in recent years, and grass Glicko penalises him for that. Since losing to Novak Djokovic in the 2011 Wimbledon final, his best result has been reaching the round of the last 16, including a very close loss to Gilles Muller last year. At 1896 points, he would be estimated to beat Federer with around 28% probability.

Milos Raonic follows behind Nadal with a gap of sixty points. He has struggled with injury over the past year but has historically been strong on grass and recently reached the final of Stuttgart, losing only to Federer. However, he withdrew from Queen’s before his second-round match, suggesting he may not be fully fit. If he can recover in time for Wimbledon, he can be dangerous.

Kei Nishikori is virtually tied with Raonic at 1835 points. Nishikori is a good player but has not had great success at Wimbledon, with fourth rounds in 2014 and 2016 being his best results. Most recently, he lost in the second round of Halle to Karen Khachanov.

Marin Cilic, last year’s finalist, trails Nishikori by just 9 points. As mentioned before, he just won Queen’s, so he appears to be in great shape. On the way to his win there, he beat strong players such as Nick Kyrgios, Sam Querrey, Gilles Muller and Novak Djokovic, making it all the more impressive. At 1826 Glicko points, Glicko gives him a 21% chance of beating the number one favourite, Roger Federer.

Juan Martin Del Potro rounds out the top 8. He has had a good season so far, reaching the semi-finals of the French Open and winning his first Masters 1000 tournament in Indian Wells. He has had some success at Wimbledon in the past, reaching the semi-finals in 2013, but since his return from injury in 2016, he has played Wimbledon twice, losing in the round of the last 32 in 2016, and round of the last 64 last year, so it will be interesting to see whether he can do better this year.

Winners and losers compared to last year

Compared to last year, the players with the biggest gains were Roger Federer (+87), Alexander Zverev (+62), Marin Cilic (+41) and Grigor Dimitrov (+57). On the other hand, Andy Murray (-79), Novak Djokovic (-51) and Tomas Berdych (-34) are considered to be somewhat weaker than they were last year by Glicko.

PlayerSkillUncertainty
Serena Williams*1977121
Simona Halep185068
Victoria Azarenka*183696
Petra Kvitova182567
Angelique Kerber182468
Maria Sharapova182378
Caroline Wozniacki181869
Karolina Pliskova181466

On the women’s side, the big asterisk is on Serena Williams. She has historically been a very strong player on grass, but she has not played on it since winning Wimbledon in 2016. At this year’s French Open, she reached the round of the last 16 but withdrew before her match against Maria Sharapova. Given her long absence, it would be surprising if she played to anywhere near her high rating of 1977, and this is reflected in the large uncertainty of 121 given to her by Glicko.

Similarly, although Victoria Azarenka’s strong historical performances still give her the third-highest Glicko rating, her recent struggles with injury mean that I gave her rating an asterisk. Most recently, she lost to Lucie Safarova in the second round of Mallorca.

Given the doubts about Williams and Azarenka, the real six favourites are Simona Halep, Petra Kvitova, Angelique Kerber, Maria Sharapova, Caroline Wozniacki, and Karolina Pliskova.

Simona Halep has just come off a win at the French Open, winning her first Grand Slam title. Last year, she lost in the quarter finals of Wimbledon, and her best result has been a semi-final in 2014. She has not played since her win at the French Open, so it will be interesting to see whether she can adapt to the grass quickly enough.

Petra Kvitova has won Wimbledon twice before, in 2011 and 2014. In addition, she won the warm-up tournament in Birmingham, and with the exception of a disappointing French Open (lost in R32), she has recently looked strong. At 1825 points, her chance of beating Halep is 47% according to Glicko.

Angelique Kerber is virtually tied with Kvitova in points. She has had some good results at Wimbledon in the past, reaching the final in 2016. Recently, she lost in the first round of Mallorca, but is still contention for Eastbourne. After a tough year in 2017, she has looked stronger again this year, losing only to Halep at both the Australian Open and the French Open.

Maria Sharapova follows closely behind. She has had some success since returning from her doping ban at Stuttgart a little over a year ago. Recently, she reached the quarter finals at the French Open and has played only an exhibition match since, losing to Maria Sakkari at the Hurlingham Club.

After winning her first Grand Slam at the Australian Open, Caroline Wozniacki, the number seven favourite, has had mixed results. She has not won a title in that period and lost in the round of the last 16 at the French Open. At the time of writing, she is still in contention for the Eastbourne title, so her result at that tournament could be a good indication of how strong she will be at Wimbledon.

Finally, Karolina Pliskova rounds out the top 8. A strong player in general, she has struggled at Wimbledon in the past, and has not progressed past the second round. Her first-round loss to Magdalena Rybarikova at Birmingham this year seems to confirm her struggles on grass, but she has shown in the past that she can play on the surface, winning Eastbourne last year, for example. It will be fascinating to see whether she can finally put in a good showing at Wimbledon.

Winners and losers compared to last year

Since last year, the players with the biggest gains have been Ashleigh Barty (+131), Caroline Garcia (+120), Sloane Stephens (+66) and Coco Vandeweghe (+63). Ashleigh Barty could be worth looking out for at Wimbledon: in addition to gaining a lot of points over the last year, she recently won the grass-court tune up event in Nottingham.

On the other hand, despite still being ranked highly by Glicko, the players with the biggest losses among top players were Victoria Azarenka (-115), Serena Williams (-86) and Maria Sharapova (-75).


Summary

This year’s Wimbledon promises to be an intriguing event. On the men’s side, the question is whether Roger Federer can defend his title. It will also be fascinating to see whether Novak Djokovic can recapture some of the form that saw him win three times in the past, whether Andy Murray can return strongly from injury, and whether Rafael Nadal can put in a strong showing again after years of difficulty on grass.

On the women’s side, the field is ranked very closely together. Can Serena Williams return strongly? If so, it is hard to count her out. However, given her long absence, Halep, Kvitova and Kerber all look like strong contenders.


Betting Strategy

 BACK – Roger Federer in the Men’s tournament

 BACK – Petra Kvitova in the Women’s tournament


related articles

Tennis: ELO Modelling

In the previous article, I gave an overview of the different approaches used to model tennis matches. In this ...

Tennis Betting Tips and Strategies: Important Stats

Professional tennis punter Jack Houghton explains the most important statistics to utilise when developing a tennis betting strategy.

Tennis Predictions Model

The Data Scientist’s Tennis Predictions Model identifies trading & betting opportunities throughout ATP & WTA tournaments around the world.  ...