Krumm, the sixth seed, broke again to take the set and twice more in the second to seal a 6-3 6-3 victory in 63 minutes.

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Sixth seed Pliskova, 18, came back from 4-1 down in the tie-break to seal victory in one hour 20 minutes.

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But the fourth seed's serve became more erratic, making four double faults, and Nadal capitalised with two breaks to seal the first set.

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