Alexander Zverev’s US Open title triumph has seen him move closer than ever to Jannik Sinner at the very top of the ATP Tour rankings.

Sinner didn’t play the US Open and Zverev dutifully capitalised by beating the likes of Ben Shelton, Karen Khachanov, and Botic van de Zandschulp to win the Grand Slam.

The German star’s second Grand Slam title has seen him move just 1810 ranking points behind Sinner ahead of the final stretch of the season.

Sinner has now made a scheduling decision which could prove vital in his attempts to keep his place at the summit of men’s tennis.

More Jannik Sinner news

The Italian has signed up to play the Vienna Open, the ATP 500 indoor tournament which takes place between October 24th and November 1st.

Sinner is the defending champion at the tournament, but his attendance at the ATP 500 event clearly shows that he is keen to bag as many ranking points as possible.

The Italian is defending 3,550 points until now and the end of the season, while Zverev is only 1,040 points, so Sinner will need to play – and win – plenty of tournaments before the season draws to a close.

Sinner won the China Open, the Vienna Open, the Paris Masters, and the ATP Finals last year and his previous performances on indoor hardcourt suggest he has what it takes to fend off Zverev.

However, there are several question marks around the Italian.

The star has not played since Wimbledon due to a knee injury, which could take some time to get truly back up to speed on the ATP Tour.

As well as that, Sinner is also set to play the China Open and the Shanghai Masters, which are traditionally two of the hottest tournaments on the calendar.

Sinner has struggled with the heat previously and even looked on the brink of retirement at the Shanghai Masters last year, before he lost to Tallon Griekspoor.

As well as fears surrounding the world No 1, Zverev is also playing some of the best tennis of his life.

The German is deservedly a two-time Grand Slam champion this year and that confidence will very likely buoy him for the rest of the ATP Tour season.

He’s an excellent hardcourt player and he has won three tournaments on this stretch previously in the Vienna Open, the ATP Finals, and the Chengdu Open.

It could be a very close run thing and Sinner signing up to the Vienna Open this year shows he’s desperate to keep hold of his world No 1 status.