The 28-year-old Yorkshireman - recently elevated to No 3 in the world - beat Egyptian qualifier Marwan El Shorbagy 11-8, 11-3, 11-0 to set up Friday’s mouth-watering clash with former world No 1 Shabana.
The two have not met since the Tournament of Champions final in New York last year, when Willstrop prevailed 3-0.
Since then, both players have suffered injury setbacks with Shabana only recently returning to the world tour following a six-month lay-off.
Willstrop, while understandably pleased with his form, knows he will have to be at his consistent best to reach the last four and a probable encounter with world No 2 Ramy Ashour, who was made to work hard for his quarter-final spot by Alister Walker before winning 8-11, 3-11, 11-6, 11-9, 11-3.
“Mentally I was good there today, I stayed focussed,” said Willstrop.
“I’ve performed consistently so far - I’m at No 3 in the world now. I don’t need to convince anyone - and getting to the final last week (in Qatar) was good.
“But it’s about producing it on a given week, and this is the one week of the year when we’re all trying to do that at the same time - and that’s the great thing about the challenge at the moment.”
Shabana, who defeated fellow Egyptian Hisham Mohamed Ashour 3-11, 8-11, 11-4, 11-9, 11-5 in his third-round match, added: “James is an amazing player.
“We’ve had so many battles. I think both of us have to raise our game for the World Open and the spectators are going to be in for a treat.”
Nick Matthew is also in action, hopefully refreshed from his marathon 100-minute third-round match with Mohamed El Shorbagy on Wednesday, to take on fellow Englishman Peter Barker.
In the women’s draw, Harrogate’s world No 2 Jenny Duncalf faces Laura Massaro.