MIAMI, FL, USA - No.21 seed Anett Kontaveit essayed a remarkable comeback to make her maiden Miami Open semifinal, storming back from 0-4 in the final set to end No.27 seed Hsieh Su-Wei's run of upsets 3-2, 6-2, 7-5 in exactly two hours.

The Estonian extends her head-to-head lead over Hsieh to 2-0, having previously defeated the former doubles World No.1 6-1, 6-3 in the first round of Guangzhou in 2015, at the end of a year during which the two players shared a coach in Paul McNamee. The result also seals Kontaveit's third semifinal at Premier 5 level or higher within the past year following her run to the last four of Rome last May and the biggest final of her career to date in Wuhan in October.

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Initially, though, Kontaveit was confounded by Hsieh's inimitable 'Su-Wei style', and the match began with an illustration of how it causes trepidation in her opponents. Players from Naomi Osaka to Petra Kvitova have discussed how the 33-year-old's ability to disguise a vast repertoire of shots causes them trouble this week; Kontaveit, perhaps mindful of the webs Hsieh can spin in extended rallies, opted largely for out-and-out first-strike tennis.

This strategy did not work out too well in the first set, as the Estonian ended up committing 18 unforced errors to nine winners and conceding her first three service games. Hsieh, for her part, was cagy and controlled, despite losing her own serve twice - including when first serving for the set. The Hiroshima champion kept Kontaveit on her toes with impeccable depth and, every so often, a sprinkling of magic, bringing out a dropshot and short angled return to gain a 5-1 lead.

Redirecting pace from line to line, Hsieh served out the set at the second time of asking and broke for 2-1, the pattern holding as the second set got under way. But it was at this juncture that Kontaveit belatedly settled, alighting on a much-needed purple patch to reel off four straight games to level the match.

The Wuhan runner-up drew gasps with her sheer raw power at times, clubbing four consecutive winners to break back for 2-2 and even swatting a clean winner off a fiendish Hsieh slice to move up 4-2. Punishing her opponent's serve remorselessly, Kontaveit frequently left Hsieh standing flat-footed as she hammered one clean return winner after another, tallying 18 to a much-improved 13 unforced errors in the second act. The 23-year-old was also able to sustain her level to fend off danger, saving one break point in each of the fifth and seventh games - moments that could have easily swung the flow of the set.

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Hsieh's own aggression had been somewhat stymied by Kontaveit's no-holds-barred approach, and it was this that the former doubles World No.1 sought to change in the decider. Taking the ball earlier and proactively steering it into awkward locations sooner in the rally, Hsieh once again began to discombobulate Kontaveit, who lapsed back into error as suddenly as she had begun zoning.

In a regrouping reminiscent of her third-set performance against Caroline Wozniacki yesterday, the Auckland and Dubai semifinalist would take 16 out of the first 19 points - including 12 in a row - to rush to a 4-0 lead.

Kontaveit clung on, though, battling through two long deuce games to regain one of the breaks. The 2017 's-Hertogenbosch champion seemed to have missed her opportunity when two ill-timed groundstroke errors allowed Hsieh to inch ahead to 5-3 - but Kontaveit, now playing her best tennis of the match in both thrilling longer exchanges as well as off the first ball, continued her surge.

Kontaveit's coach Nigel Sears had urged her to come forward to put points away during an on-court coaching session at the start of the set, and doing so would prove key.

As a tiring Hsieh attempted to serve out the match, the Brisbane quarterfinalist nailed a drive volley to break back; two games later, with Hsieh poised on the brink of a tiebreak at 40-0, Kontaveit again reeled her in. The final two points epitomised how she had pulled off her escape: another clean return winner followed by a careful, but emphatic, smash that took her tally of winners to 44.

Kontaveit's debut in a Premier Mandatory semifinal will either be a clash of power against No.3 seed Petra Kvitova - whom the Estonian has already defeated this year, in the second round of Brisbane - or another stylistic contrast against the slices and finesse of No.12 seed Ashleigh Barty.