The unseeded 20-year-old produced a dominant performance to beat his English opponent 12-10, 11-5, 11-8 at the PSA World Series tournament taking place at the Khalifa International Tennis and Squash Complex in Doha.

Elias, who began his season with victory over three-time world champion Nick Matthew of England at last month’s NetSuite Open in San Francisco, came from behind in the opening game to counter Willstrop's trademark accuracy and set up the foundations for the win.

"Last time we played it was about a year ago and he [Willstrop] played so well that day that I couldn’t do anything," Elias said.

"It’s always hard to play against a player like him so today I just tried to apply as much pressure as I could throughout the match and keep my concentration levels high.

"The first game was crucial.

"I think I was down 8-3 and I just tried to change things up and move him around the court.

"I feel confident on court and feel like my game is coming together well so I hope this can be a good tournament for me."

Elias is due to go up against Saurav Ghosal for a place in the quarter-finals after the Indian number one secured his own upset at the expense of England's number three Daryl Selby.

Ghosal, who fell as low as number 30 in the rankings earlier this year following a poor run of form, oozed confidence as he dominated Selby from the outset.

The 31-year-old used his pace and movement to expose his opponent and looked like a player renewed as he prevailed 11-4, 11-8, 11-2.

Victory was Ghosal’s first over Selby and also ensured his place in the second round of the event for the first time in his career.

"I'm enjoying playing and feeling privileged to be competing at great events such as this in Qatar," Ghosal said.

"I'm trying to do the things I know I'm capable of - things which in the past I haven't executed as well as I should have.

"If I can enjoy it for the most part then I feel I can give a good account of myself."

Hong Kong's Leo Au was another surprise winner on the opening day of action as he recorded a 7-11, 11-7, 11-8, 11-4 win over Australia's Ryan Cuskelly.

World number one Gregory Gaultier of France marked his return from injury with a comfortable 11-6, 11-2, 11-9 victory over Mexico's Cesar Salazar.

Two-time tournament winner Mohamed ElShorbagy of Egypt was among the other victors on the day, beating England’s Chris Simpson 11-7, 11-9, 11-5.

Compatriots Fares Dessouky, Zahed Mohamed and Ali Farag also progressed.

Dessouky defeated home favourite Abdulla Mohd Al Tamimi 11-6, 11-8, 11-5, while Mohamed overcame France’s Gregoire Marche 11-6, 5-11, 11-6, 8-11, 11-2 and Farag downed fellow Egyptian Karim Ali Fathi 11-7, 11-5, 11-1.