World number one Mohamed beat Australia’s Ryan Cuskelly 11-4, 11-6, 11-6, while world number six Marwan overcame South Africa’s Stephen Coppinger 4-11, 11-2, 11-8, 11-7.

It sets up a last-eight showdown on Monday (January 16) that will see the Egyptian siblings meet for the seventh time on the PSA World Tour - with elder brother Mohamed enjoying a 100 per cent record to date.

They last met at the same stage during the 2016 US Open, when Mohamed claimed a 3-0 win on his way to winning the title.

But after defeating Cuskelly in straight-games tonight, the defending TOC champion admitted that he expects his brother to push him all the way this time around.

"I've won all our matches so far, but he's learning every time we play and he's getting closer and closer to that win," Mohamed, 26, said.

"It's something special to have two brothers playing and competing against each other - it's like the Williams sisters in tennis - and it's something our family can be very proud of.

"One day he will beat me, but hopefully not at this tournament because I felt like I played very high quality squash today.

"I have trained hard in the past month and I'm feeling good, so hopefully I can carry that on."

Before the encounter, 23-year-old Marwan said: "I'm excited to be in the quarters.

"To play my brother in the last eight in a setting like Grand Central Terminal is something I never dreamed would happen.

"I've been close to him a few times and I'll try to step up another level on Monday.

"He's playing well, but so I am, so we'll see what happens."

The winner of the match could find themselves lining up against 2009 TOC winner Grégory Gaultier of France in the semi-finals after the 2015 world champion came from two games down to defeat Egypt’s Fares Dessouky, 9-11, 8-11, 11-3, 11-7, 11-7.

The 22-year-old Dessouky recorded his first career win over Gaultier in their last meeting, during last August's Hong Kong Open, but Gaultier found a way back into the contest, stepping up and asserting his physicality to extend the rallies and edge a decisive fifth game.

In the women's tournament, which got underway with first-round action today, there were comfortable victories for defending champion Nour El Sherbini of Egypt and eight-time world champion Nicol David of Malaysia.

El Sherbini easily dispatched Hong Kong's Joey Chan 11-6, 11-8, 11-4, while David, who fell to a 12-year low of number seven in the world rankings last month after a disappointing 2016 campaign, got off to a positive start with an 11-3, 11-3, 11-4 triumph over former world number two Jenny Duncalf of England.

Current world number two Nouran Gohar of Egypt secured a similarly straight-forward passage into the second round with an 11-9, 11-7, 11-6 win over fellow Egyptian Mayar Hany.

Qualifier Salma Hany Ibrahim, also from Egypt, produced the upset of the day to defeat world number eight Alison Waters of England 8-11, 11-1, 11-13, 11-9, 11-2.