The Canadian Open comes to a close today and with that, the Cincinnati Open will commence next week in what is the final event before the US Open takes place. For now, Carlos Alcaraz remains No. 1 in the rankings and will be the top seed going into Flushing Meadows. It would have stayed that way had the Spaniard won in Toronto no matter the result in Cincinnati.

However, Alcaraz bowed out in the quarterfinal stage to Tommy Paul in the Canadian Open which will give Djokovic — who has no points to defend — a much better chance of regaining the No. 1 ranking if certain results go his way in Cincinnati. So with all that said, here's a look at the various scenarios in which Alcaraz and Djokovic can enter the US Open as the World No. 1 with their results at the Western and Southern Open.

Before we get started, here's a quick reminder of the current ATP rankings as things stands:

  1. Carlos Alcaraz – 9,225 points
  2. Novak Djokovic – 8,795 points

What is Carlos Alcaraz's lead over Novak Djokovic after his early Toronto exit?

Alcaraz only reached the second round in Canada last year and so, having made the quarterfinals, he's actually increased his lead over Djokovic by gaining 170 points (he earned 10 points already just by playing a game in Toronto).

That puts his ranking at at 9,395 points when the rankings get updated on Monday and gives him a 600-point lead over the Serbian superstar who has 8,795 points.

How many points is Carlos Alcaraz defending in Cincinnati?

Alcaraz reached the quarterfinals in Cincinnati last year after losing to Cameron Norrie in the last eight. That means he's defending 180 points and has to reach that stage again if he wants his points tally to remain at 9,395 points. Should he emerge victorious at the Masters event, however, the 20-year-old will earn an additional 820 points which would take his tally to 10,215 points.

What results does Carlos Alcaraz need to remain No. 1?

The simple fact is, Alcaraz goes into the US Open as the top seed provided he wins in Cincinnati which will undoubtedly be the goal. However, the two-time Grand Slam winner can also retain top spot if he reaches the final. In that case, he would remain at the summit even if it's Djokovic who defeats him and wins the tournament. However, that would give him just a 20-point lead over the 36-year-old.

Finally, even if Alcaraz goes out early and loses his 180 points, he will remain No. 1 provided Djokovic doesn't make it past the semifinal stage.

What results does Novak Djokovic need to remain No. 1?

Likewise, Djokovic's only real chance of becoming No. 1 hinges on him making the final at the Cincinnati Open where he will earn 600 points if he finishes second and 1,000 points if he wins the whole thing. Should he win the tournament or even finish second while Alcaraz fails to reach the last eight, Djokovic will overtake him to the top spot.

Djokovic will also overtake Alcaraz if he wins the tournament and the latter only makes it to the last four. In a scenario where Alcaraz fails to reach the last eight or doesn't compete and Djokovic only finishes as a runner up, we'll have a unique situation where both men will be tied for points.

In that case, the US Open seeding will come down to who has the most points from the main draws of Grand Slams, ATP Finals and mandatory Masters 1000 events. Should they still not be separated, other factors will be looked at such as which player has played in fewer tournaments during the 2023 season.