ATP Finals 2020: Likely semifinal matchups, and what Rafael Nadal & Novak Djokovic need to do to qualify

The 2020 ATP Finals has had its ups and downs. It has thrown up some thrilling encounters, as can be expected of the world's eight best players, but also produced some one-sided duds. Most notably though, the world's two best players - Novak Djokovic and Rafael Nadal - have still not confirmed their spot in the semifinals.

With the final stage of the round-robins set to take place on Thursday and Friday, a multitude of semifinal matchups are still possible. But before we look at the various permutations and combinations, here are the rules for qualification out of the group stage as per the Nitto ATP Finals website:

The final standings of each group shall be determined by the first of the following methods that apply:

a) Greatest number of wins;

b) Greatest number of matches played;

c) Head-to-head results if only two (2) players are tied,

d) If three (3) players are tied, then:

If three (3) players each have one (1) win, a player having played less than all three (3) matches is automatically eliminated and the player advancing to the single elimination competition is the winner of the match-up of the two (2) players tied with 1-2 records; or

Highest percentage of sets won; or

Highest percentage of games won; or

The player positions on the Emirates ATP Rankings as of the Monday after the last ATP World Tour tournament of the calendar year.

If (i), (ii), (iii) or (iv) produce one (1) superior player (first place), or one (1) inferior player (third place), and the two (2) remaining players are tied, the tie between those two (2) players shall be broken by head-to-head record

Against that background, here's a look at the possibilities of who plays whom in the semifinals of the Nitto ATP Finals 2020:

Dominic Thiem set to recreate a 2020 Grand Slam final at ATP Finals 2020

Dominic Thiem (L) and Novak Djokovic at the 2020 Australian Open

The players were divided into two groups at the start of the men's draw, which were named in celebration of the 50th anniversary of the ATP Finals. Group Tokyo 1970 contains Novak Djokovic, Daniil Medvedev, Alexander Zverev and Diego Schwartzman while Group London 2020 has Rafael Nadal, Dominic Thiem, Stefanos Tsitsipas and Andrey Rublev.

Although they have put up spirited displays in their matches so far, both the debutants - Andrey Rublev and Diego Schwartzman - have been eliminated from the tournament already.

In Group London 2020, Dominic Thiem has by far been the most impressive and dominant player so far. The Austrian first defeated Stefanos Tsitsipas 7-6 4-6 6-3 in a repeat of last year's final, and he followed that up with a victory over World No. 2 Rafael Nadal in consecutive tiebreaks.

Many believe Nadal's match against Thiem is the best match of 2020 in terms of shot-making quality. The result also means Thiem has topped the group, since the only players who can have the same wins as the Austrian (assuming he loses to Rublev) - Nadal or Tsitsipas - have a losing head-to-head against him.

Meanwhile Rafael Nadal's encounter with Stefanos Tsitsipas in the final match of the group stage is a de facto quarterfinal. Both players have lost to Dominic Thiem and defeated Andrey Rublev, meaning only one of them can get to two wins and reach the semifinals.

Novak Djokovic (L) and Rafael Nadal at the 2020 French Open

There is an almost mirror image of the situation in the other group. Daniil Medvedev has picked up consecutive straight-sets wins - against Alexander Zverev and Novak Djokovic. This means the Russian has topped the group, and that the match between Zverev and Djokovic is also a virtual quarterfinal.

With their unbeaten run, Medvedev and Thiem have ensured that they cannot meet each other in the semifinals (since the topper of one group faces the second player from the other). However, there are several other possibilities still alive.

Dominic Thiem could face Djokovic, in a repeat of the Australian Open final, or Alexander Zverev, in a repeat of the US Open final. That depends purely on who wins the match between Djokovic and Zverev; the winner gets to face the Austrian.

In the other semifinal, Medvedev will be facing either Stefanos Tsitsipas or Rafael Nadal for a place in the final.

Following their remarkable encounter in the group stage, Thiem and Nadal could potentially face each other in the tournament once again - in the final. For that to happen, Thiem would have to beat Djokovic or Zverev while Nadal (assuming he beats Tsitsipas) would have to get past Medvedev.

Tsitsipas and Zverev have both been in shaky form this week. However, due to the unique nature of the tournament, they still stand an outside chance of winning the title.

That's not to forget the World No. 1. Despite a disappointing outing against Medvedev, Novak Djokovic could yet have a big say in the race. Looking for a record-equaling sixth year-end title, the Serb could potentially recreate this year's Roland Garros final against Nadal. But for that he will have to defeat Alexander Zverev and Dominic Thiem in consecutive days.

The bookmakers' favorites to reach the final are Thiem and Medvedev, given their flawless starts. That match could be a blockbuster in itself, given their contrasting playing styles and good form at the moment.