London, July 9: Simona Halep came through a gripping first-set examination to see off China's Zhang Shuai 7-6 (7-4) 6-1 and book a place in the semi-finals of Wimbledon for the first time since 2014.
Halep, the highest-ranked player left in the draw, is chasing a second career grand slam but had to weather a considerable storm against outsider Zhang.
A break down, the world number seven escaped a marathon sixth game to halt Zhang's momentum before stealing the opener on a tie-break.
After those absorbing first 58 minutes, the second set was a more serene affair and Halep will face either Elina Svitolina or Karolina Muchova as she bids to reach a maiden final at the All England Club.
Zhang had never won a main draw match at Wimbledon until this year but, having already seen off seeds Caroline Garcia and Caroline Wozniacki, raced into a 3-0 lead in just over 10 minutes on Number One Court.
A pinpoint backhand into the back-right corner was the jewel in the 30-year-old's early break as her powerful, flat groundstrokes exuded composure and authority.
Halep's forehand was misfiring, and she had to negotiate a considerable crisis at 1-4, scrambling to save four break points and eventually hold.
The high-class and gruelling rallies required to do so appeared to play the 2018 French Open champion into form and Zhang coughed up a break in the next game with a double fault.
The set remained on serve from that point and Halep managed to keep her opponent's relentless attacks at arm's length to take the breaker 7-4.
If the Romanian star had a sense the storm had passed, it was confirmed when Zhang sent a tame forehand into the net to be broken for 3-1.
Halep consolidated with a hold to love and the world number 50 was predictably unable to relocate her sparkling earlier form.
STATISTICAL BREAKDOWN Simona Halep  bt. Zhang Shuai 7-6 (7-4) 6-1
WINNERS/UNFORCED ERRORS Halep - 17/13 Zhang - 22/29
ACES/DOUBLE FAULTS Halep - 1/1 Zhang - 1/2
BREAK POINTS WON Halep - 3/6 Zhang - 1/5
FIRST SERVE PERCENTAGE Halep - 76 Zhang - 71
PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE Halep - 72/44 Zhang - 67/41
TOTAL POINTS Halep - 74 Zhang - 61