World number one and two-time Madrid champion Djokovic, meanwhile, walked into the semi-finals when ninth seed Marin Cilic withdrew before their match with stomach problems.
“I am sorry to announce that I must withdraw from today’s match. I have had a terrible night dealing with a case of food poisoning,” wrote Cilic in a statement.
“I am extremely disappointed to have my time in Madrid end in this way. Thank you for the support.”
In the semi-final on Saturday, Djokovic will face either Roger Federer or 2018 finalist Dominic Thiem.
Halep awaits either Dutch seventh seed Kiki Bertens, a finalist in Madrid last year, or 2017 US Open champion Sloane Stephens.
“It’s such a nice feeling to be back in the final here. I really enjoy playing in Madrid, it motivates me,” Halep said.
The third seed comfortably claimed the opening set but let her game lapse slightly in the second.
Bencic, who opened the door for Halep to possibly return to the top of the world ranking with her quarter-final defeat of current number one Naomi Osaka, took a tight second set in a tiebreaker.
But Halep pulled herself together to blitz Bencic in the third as she raced to a victory that increases her chances of returning to the top of the pile.
“I was rushing too much in the second-set tiebreaker,” Halep said. I was missing too many easy balls — I lost control of that tiebreak.
“In the third I just started over again, I played smarter, opening up the court and being more aggressive.”
Article source: https://sports.ndtv.com/tennis/madrid-open-simona-halep-reaches-final-novak-djokovic-gets-free-pass-2035950