Novak Djokovic came back from a set down to beat Italian Matteo Berrettini 5-7, 6-2, 6-2, 6-3 to go to the US Open semi-finals for the third time in a row. The Serb is currently just two wins away from completing a calendar-year Grand Slam with a record 21st major.

Djokovic and Berrettini have only met three times, two of which were this year in high-stakes situations: the Wimbledon final and the quarterfinals of the French Open. Both matches were won in four sets by the Serbian World No. 1.

On Wednesday, the 25-year-old Italian had a third chance to upset Djokovic’s Grand Slam hopes, but he failed to take advantage of it, converting only one of five break chances, which came in the first set.

In the following round, Djokovic will face fourth seed Alexander Zverev, the man who ruined Djokovic’s dream for a ‘Golden Slam’ by defeating him in the Tokyo Olympics semi-finals last month.

Zverev, the top player in men’s tennis, advanced to the final four with a 7-6 (6) 6-3 6-4 victory over unseeded South African Lloyd Harris, extending his winning streak to 16 games.