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The two-time Stuttgart champion, who recently linked up with Rafael Nadal's former coach Francisco Roig, needed exactly an hour and a half to reach the quarter-finals.

She will meet either Alycia Parks or Mirra Andreeva in the last eight, after the Russian fought back to defeat 2025 champion Jelena Ostapenko in a last-32 tie.

Swiatek broke at the very first attempt, and although Siegemund fought back in game five, the former world No.1 swiftly registered two more breaks to take the opening set.

She had to have more patience in the second, which started with five straight holds. And once again, after Swiatek did finally break, she surrendered that advantage to leave the set back on serve at 4-3.

But Swiatek was not to be denied, and she converted her second break point in game eight to wrestle back the initiative, before serving out her first clay-court win of the year.