LONDON - Matteo Berrettini defeated world number five Dominic Thiem of Austria 7-6(3), 6-3 here on Thursday, becoming the first Italian to win a singles match at the ATP World Tour Finals.

Berrettini, 23, came to London as the debutant of the year-ending tournament. The world number eight lost hope of reaching the semifinals after falling to Novak Djokovic and Roger Federer in the previous two group matches, but finally brought home a win to make history for his country. His compatriots Corrado Barazzutti and Adriano Panatta both went 0-3 in the season finale more than 40 years ago.

"It was a great week so far," said Berrettini, who began this season with a ranking outside top 50. "Before the week started, my team talked a little bit and we said to each other, Let's enjoy this week."

Thiem has qualified for the semifinals for the first time after beating six-time champion Federer and five-time winner Djokovic. The 26-year-old seemed a little bit low in momentum and was far away from his best.

"It's a bit of a tricky situation to know that I'm already through. So all the attention, the adrenaline is set down a little bit," admitted Thiem. "Of course I was still trying to win that match 100 percent, but also, in the same time, I knew in my head that I have to take care for Saturday, because obviously it's the way more important match there."

Later this evening, Djokovic and Federer will play their 49th encounter in the last round match of Group Bjorn Borg, both need to win so as to book a semifinal place.