The Italian, who is 11th in the FedEx ATP Race To Turin, continues his campaign to reach the Nitto ATP Finals, to be held on home soil 14-21 November. The top seed in Sofia recovered from both a 2-5 deficit in the first set and 2-4 down in the second to advance in straight sets.
“It’s not easy coming back every time, you would prefer to stay up. Especially in a match like this,” Sinner said. “I just tried to stay focused, try to make him think a little bit. In the first set it worked, when he was serving for the set he made a couple of unforced errors.
“I just tried to stay solid and in the second set when I was 2-4 down I tried to hit a little bit faster and strong, especially in the last game.”
Sinner improves his ATP Head2Head against the Australian to 2-1, avenging a 6-3, 6-4 defeat against Duckworth earlier this year in Toronto.
“It feels very good to be honest,” Sinner said. “Today was a very tough match. I lost the last one against him in Toronto and he was in a very positive situation, winning a Challenger, making the final last week. It was not easy for me and it was a very close match, especially the first set.”
Duckworth, a finalist in Nur-Sultan last week, had won 11 of his past 12 matches at all levels prior to the match. The 29-year-old Australian currently stands at a career-high No. 56 in the FedEx ATP Rankings.
“Playing here once again in Sofia is very special for me,” Sinner said. “I am very proud of myself, knowing that tomorrow is a very tough challenge in front of me. So I will try to be ready for tomorrow.”
Sinner is a three-time ATP Tour champion, adding two more titles to his collection earlier this year in Melbourne and Washington.