All the important stats of the 4 US Open men's semifinalists - Djokovic, Zverev, Medvedev & Auger-Aliassime

The US Open has featured three different pairs of men's singles finalists over its previous three editions. One half of every pairing is absent in this year's draw - Juan Martin del Potro from 2018, Rafael Nadal from 2019 and Dominic Thiem from 2020. And the other half from every pairing features in the semifinals of the 2021 US Open.

Novak Djokovic, Daniil Medvedev and Alexander Zverev are all in familiar territory. Felix Auger-Aliassime, on the other hand, finds himself in the final four for the first time at a Grand Slam.

Which of the four semifinalists has been statistically the most dominant until this stage of the tournaments? Here, we do a round-by-round breakdown of the draw and try to make some sense of the numbers.

Note: The glossary of the abbreviations used in the article can be found here.

US Open Round of 128

Daniil Medvedev had the toughest first round on paper, but he made light work of his opponent, Richard Gasquet. The Russian especially excelled in the return department, winning 47% of the points on the Gasquet serve. He was also the strongest in this round behind his second serve, winning 67% of such points.

In totality though, Alexander Zverev was the strongest on serve in the opener. The German won 90% of his first-serve points and 81% of his overall service points in the first round. He also recorded the highest differential percentage between winners and unforced errors (15%).

Medvedev, meanwhile, recorded the highest dominance ratio (1.49). Even though Zverev matched him closely, we give the edge to the Russian as the best performer in the first round, owing to his opponent having a higher Elo rating than Zverev's.

Round of 64

While Alexander Zverev was nearly as good as Daniil Medvedev in the first round, he was the best by a margin in the Round of 64 - where he faced Albert Ramos-Vinolas. The German recorded the best win-percentages both on serve (83%) and on return (52%), thus recording the highest dominance ratio of all the four semifinalists across all the five rounds - 1.73.

Novak Djokovic, meanwhile, recorded the highest differential percentage between winners and unforced errors in this round (8%). Felix Auger-Aliassime, on the other hand, recorded a negative score for the same (-3%).

Round of 32

In the third round, Novak Djokovic faced the toughest opponent by Elo rating (Kei Nishikori), while Felix Auger-Aliassime faced the toughest by ranking (Roberto Bautista Agut).

Alexander Zverev and Daniil Medvedev faced easier opponents on paper and they once again got it going - on serve and return respectively. The Russian won 54% of his return points, while Zverev won 76% of his service points.

It must, however, be noted that the German's opponent Jack Sock retired midmatch with an injury. That inflated Zverev's differential percentage between winners and unforced errors to 14%.

Djokovic recorded a negative differential score this time around (-3%), while Medvedev scored the best dominance ratio (1.48) and was thus the best performer in the Round of 32.

Round of 16

In the Round of 16, Alexander Zverev faced the toughest opponent by both Elo and ranking - Jannik Sinner. The difficulty of the matchup showed in his performance as he ended the match with a negative differential percentage between winners and unforced errors (-1%).

Daniil Medvedev, on the other hand, dominated this round in every department. The Russian won 74% of his service points, 47% of his return points and 75% of his net points - all of which are the best figures for this round. Consequently, Medvedev scored the best dominance ratio (1.40) and also recorded the best differential percentage (15%).

Quarterfinals

Like Alexander Zverev's in the fourth round, Novak Djokovic's opponent in the quarterfinals was unarguably the strongest on paper - Matteo Berrettini. However, the Serb rose to the occasion and produced his finest performance of the tournament after losing the first set.

Despite the Italian boasting one of the most powerful serves in the game, Djokovic won the highest percentage of return points in this round (44%).

The 34-year-old also won the highest percentage of points behind his second serve in this round. However, Daniil Medvedev was the best on serve overall, winning 74% of his service points.

The Russian marginally edged out Djokovic for the best dominance ratio (1.28), while Zverev ended up with the best percentage differential (9%).

That said, the fact that Djokovic registered near-similar figures at a greater difficulty level on paper, makes him the best performer in the quarterfinals.

Overall stats

Combining the stats obtained from all five rounds of action, we arrive at the following results from each of the categories:

Opponent strength

Even though Novak Djokovic has faced the easiest opponent by ranking on average (86), they have been the toughest by Elo (1767). On the contrary, Daniil Medvedev has had the easiest draw by Elo (1694) and the toughest by ranking (71).

Serve stats

Alexander Zverev in action against Lloud Harris in the quartefinals of US Open 2021

Alexander Zverev is the clear winner here. He has been landing the highest percentage of first serves on average (71%) and winning the highest proportion of points behind them (84%). Overall, he has won the highest percentage of service points on average as well (76%), and faced the fewest number of break points (11).

Meanwhile, Felix Auger-Aliassime has recorded the highest number of aces (85), and Medvedev has won the highest percentage of points on average behind his second serve (58%) and also committed the fewest double-faults (10). Djokovic, on the other hand, has saved the highest percentage of break points (75%).

Return stats

Novak Djokovic in action against Matteo Berrettini in the quarterfinals of US Open 2021

Novak Djokovic and Daniil Medvedev have been the best returners over the past week and a half. The Serb has won the highest percentage of return points on average, both against the first serve (40%) and the second (50%). Medvedev, on the other hand, has won the highest percentage of return points on average (48%).

The Russian has converted the highest percentage of break points (49%) while Djokovic has raised the highest number of break points (68) and converted the most as well (32).

Net points

Felix Auger-Aliassime in action against Carlos Alcaraz in the quarterfinals of US Open 2021

Felix Auger-Aliassime has both played the highest number of net points (159) and won the most (107). However, when it comes to the percentage of net points won, Alexander Zverev has the best figures (76%), winning 57 of 75 trips to the forecourt.

Novak Djokovic, on the other hand, has been the most dangerous player when his opponent has been at the net, as he has won 46% of such points.

Distance per point

Alexander Zverev has played the fewest number of points on his way to the semifinals - 854 - which is just one shy of Daniil Medvedev's 855. However, the German has covered 4.7 km less.

Medvedev has covered 31.39 meters per point he has played - a notch greater than the other three semifinalists. That number reads 25.14 for Auger-Aliassime, 25.93 for Zverev and 26.56 for Djokovic.

Winners, errors & dominance ratio

Daniil Medvedev in action against Botic van de Zandschulp in the quarterfinals of US Open 2021

Felix Auger-Alassime has hit the highest number of winners in the tournament thus far (235) while Daniil Medvedev has committed the fewest unforced errors (106).

In terms of the percentage of winners hit per point played, Auger-Aliassime and Zverev have both struck a winner 21% of the time - the highest figure in this department. The best percentage of unforced errors is again recorded by Medvedev - 12%.

While the percentage differential reads the same for Zverev and Medvedev (8%), the Russian's average dominance ratio is a cut above the rest - at 1.42.

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