ATP Finals 2025: Carlos Alcaraz and Jannik Sinner prepare for the first battle of the end of the year in Turin

The battle is about to start again.

Carlos Alcaraz emphasized this with two emojis – a number one and a sword fight – in an Instagram post with Jannik Sinner after they trained ahead of the ATP Finals on Friday.

Whether Alcaraz or Sinner will finish as world number one at the end of the year is a major point of interest at this weekend’s season-ending event in Turin.

Ending a long and grueling season as Player of the Tour is a prestigious accolade, rewarding their brilliance and consistency over the past 12 months.

Sinner retaining the title will be even more impressive given that the 24-year-old Italian has not played for three months, having been suspended for failing two drug tests.

Spaniard Alcaraz finally overtook his rival at the top of the world rankings in September, ending Sinner’s 65-week reign by winning his final Grand Slam of 2025 in New York.

Now the clear two-horse race moves to the final event of the season, with the 22-year-old Alcaraz looking the favorite to win their duel.

“If Carlos plays well there will be no chance, and it doesn’t matter what my score is,” Sinner said.

BBC Sport breaks down each player’s permutations and who can stop them. At the bottom of the page, you can vote for who you think will win in Turin.