(CNN) -- Serena Williams will get the chance to avenge her worst defeat in 16 years on Sunday when she goes head to head with Simona Halep in the WTA Finals finale in Singapore. The world No. 1 was humbled by the Romanian 6-0 6-2 in the group stages of the tournament earlier in the week, but following Williams' semifinal victory over Caroline Wozniacki and Halep's over Agnieszka Radwanska, the pair are set to do battle once more. Few would bet against Williams clinching a third successive title and her fifth overall at the season-ending finals, but Halep will be the fresher of the two women after dispatching her Polish opponent 6-2 6-2.
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Serena Williams battles past Caroline Wozniacki in WTA Finals semi
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Simona Halep beats Agnieszka Radwanska in other semi
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Romanian humbled the world No. 1 in group stages earlier in the week
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Williams looking to clinch a fifth WTA Finals title; Halep reaches final in first appearance
@placeholder saved a further two match points, before Williams finally clinched the tiebreak 8-6 in a marathon deciding set lasting 76 minutes.