MIAMI, FL, USA - No.2 seed Simona Halep remains on course to retake the World No.1 at the Miami Open after a 6-4, 7-5 victory over No.18 seed Wang Qiang in one hour and 37 minutes - in which she had to recover a 1-5 deficit and save three set points in the second set.

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It is the Romanian's second win in as many meetings with fellow 27-year-old Wang in the March hard court swing, following her 7-5, 6-1 triumph in the fourth round of Indian Wells last year, and puts her just one win away from moving back up to the top spot two months after being deposed by Naomi Osaka.

In a match characterized by probing baseline rallies, it was Halep who proved more successful at opening up the court and retaining her consistency over the longer exchanges. With neither player able to hit through each other early in the point, the Roland Garros champion was able to gradually shift from neutral into aggressive, steering the ball around the court until Wang was unable to keep up - finding particular joy by wrongfooting the Chinese No.1 repeatedly.

Halep, who survived a marathon third round against lucky loser Polona Hercog before straight-setting Venus Williams for the fourth time in a row, was a touch more error-prone than she would have liked, committing 19 in the first set and dropping serve twice. But the Doha runner-up was razor-sharp on return, coming up with some of her finest shotmaking just when Wang was on the verge of holding: the Nanchang and Guangzhou champion dropped her second and third service games from 40-15 and 40-0 up respectively, unable to take enough control to close the door.

After a scrappy start that saw five breaks in the first six games, the final four games of the first set all went to the server, with Halep delivering an authoritative hold to close it out with a forehand down the line winner on her first set point.

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Though the former World No.1's form carried over for an immediate break with another forehand winner - this time set up immaculately with heavily topspun backhands that pushed Wang off the court - the second set would be one of dramatic momentum shifts. Down a set and a break, Wang finally had enough of being pushed around the court - and stepped in to use her own power to dictate proceedings.

The Wuhan and Beijing semifinalist edged through two multi-deuce tussles on Halep's serve to break twice and move up 3-1, and then started zoning, smacking winners from all corners of the court to reel off 12 points, and five games, in a row for a 5-1 lead.

But with the set seemingly on the verge of going to a decider, the pendulum swung again. Halep, swinging freely and even approaching the net with intent and success, broke back - and suddenly, the Montréal champion was back in business.

Almost unable to miss, Halep was magnificent on both defence and offence as she stormed back to erase Wang's lead as quickly as the World No.18 had built it, rushing through 25 out of the last 31 points to deliver a 'hidden bagel' - six straight games from 1-5 down.

In the midst of this stretch, Wang's best opportunity to force the decider had been when she held three consecutive set points as Halep served at 4-5 - but the 2018 Australian Open finalist saved all of them in fine style with a sharp volley, an inside-out forehand winner on the line and a punishing extended rally before levelling the score with the shot of the match - a breathtaking backhand winner down the line, bunted into the far corner at full stretch.

Wang's errors were mounting in the face of Halep's comeback, and in the final game her backhand in particular collapsed, offering up three unforced errors to take her total to 25. Halep, though, will be proud both of her fighting spirit in a second set that seemed all but lost - and her impeccable execution to raise her level and steal it from Wang.

Back in the Miami semifinals for the second time, and first time since 2015, Halep will bid to make her first final in Florida - and with it, retake World No.1 - against either No.5 seed Karolina Pliskova or 19-year-old Marketa Vondrousova, her conqueror two weeks ago in Indian wells.