(CNN) -- Rafael Nadal completed a perfect sweep of his matches in Group A of the ATP World Tour Finals by beating Tomas Berdych Friday -- his victory enabling a grateful Stanislas Wawrinka to accompany him into the semifinals in London. Wawrinka and his supporters breathed a sigh of relief after Nadal wrapped up a 6-4 1-6 6-3 victory over his Czech opponent to go through as group winner. The match had been in the balance when Berdych hit back to level at one set all with a display of power tennis that had the top seed wobbling, but he could not sustain the effort.
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Stanislas Wawrinka qualifies for semifinals at ATP World Tour semifinals
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Beats David Ferrer in three sets in Group A
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Rafael Nadal's win over Tomas Berdych seals Wawrinka's passage
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No.1 Nadal has to battle past Berdych in three sets
Wawrinka, who beat Berdych in his opening match before losing to Nadal, raced into a 5-2 lead in the opener before @placeholder battled back to force a tiebreaker, which he took 7-3.