Mohamed ElShorbagy is out to retain his title at the Oracle NetSuite Open ©Getty Images

Organisers of the Oracle NetSuite Open have confirmed all participants must be fully vaccinated against COVID-19 or provide a negative test taken within 48 hours of admission in order to attend the event in San Francisco.

The world's top players have arrived in San Francisco for the tournament, the latest stop on the Professional Squash Association (PSA) World Tour.

The tournament at Embarcadero Plaza, a PSA World Tour Gold-level event, is set to begin tomorrow and conclude on Monday (September 27).

It was cancelled last year because of the COVID-19 pandemic, which caused widespread disruption to the global sporting calendar.

The majority of the top 15 in the world have entered the men's draw, where Mohamed ElShorbagy will aim to retain the title he won in 2019.

Egyptian ElShorbagy takes on Mohamed Abouelghar in the first round and has a potential meeting with 2016 world champion Karim Abdel Gawad in the quarter-finals.

Ali Farag, also of Egypt, is the second seed and plays Mostafa Asal in his opening encounter, while Tarek Momen completes an all-Egyptian top three.

Peru's Diego Elias has been forced to withdraw from the tournament because of a recurring back injury.

Elias had been due to face Egypt's Mazen Hesham in the first round.

In the women's draw, world number two Nouran Gohar is the top seed and entertains Canada's Hollie Naughton tomorrow.

The former British Open champion is expected to face a strong challenge from second seed Amanda Sobhy, who will aim to make the best use of home advantage.

Sobhy's first opponent will be Nadine Shahin of Egypt.