Sixth seed Alexander Zverev dug deep on Wednesday as he defeated Russian qualifier Roman Safiullin to advance to the Roland Garros third round.
Safiullin did not show any signs of being overwhelmed on the big stage, but it was Zverev who emerged the victor, 7-6(4), 6-3, 7-6(1), in what was another intense battle against a player who came through the qualifying stages.
The 24-year-old Zverev, who is now 20-8 on the season, will next play a Serbian: Laslo Djere or Miomir Kecmanovic.
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Zverev, who recovered from two-sets-to-love down against qualifier Oscar Otte on Sunday, was given a stern test in the 60-minute first set. He was broken when serving for the set at 6-5, but got off to a strong start in the tie-break. The German came back from 1-3 down in the second set, and a 1-4 deficit in the third set.