I was giving Rafael Nadal free points without himself doing much: Stefanos Tsitsipas

Defending champion Stefanos Tsitsipas believes he used the wrong match tactics against Rafael Nadal at the Nitto ATP Finals on Thursday. The Spaniard ended up winning 6-4, 4-6, 6-2 to qualify for the semifinals of the season-ending event, while also knocking Tsitsipas out in the process.

Rafael Nadal will now play Russia's Daniil Medvedev on Saturday as he chases his first ever ATP Finals title. In the other semifinal, Dominic Thiem will meet the winner of the round-robin clash between Novak Djokovic and Alexander Zverev on Friday.

After Thursday's clash, Stefanos Tsitsipas let out his frustration at being unable to make Rafael Nadal work harder for the points, saying that he was 'too aggressive'.

“I don't even know what I was trying to do, honestly,” Tsitsipas said. “Trying to be way, way too aggressive. I was giving him (Rafael Nadal) free points without really, you know, himself doing much or hurting me from the back."

The 22-year-old also admitted he was let down by his serve against Rafael Nadal. Tsitsipas got only 57% of his first serves in during the match, and was able to win just 44% of his second serve points.

“I should have handled it a little bit more clever and patiently, but it didn't happen," the Greek added. "My serve was not there when I needed it, and these guys, you just have to be there. I wasn't fully present. I wasn't playing in the moment. Quite disappointed with that. But that's life."

This is the second year in a row that Rafael Nadal has defeated Stefanos Tsitsipas at the ATP Finals in the round-robin stage. The Spaniard has now improved his head-to-head record against the 22-year-old to 6-1.

There are a few positives I can take from 2020: Stefanos Tsitsipas after loss to Rafael Nadal

Stefanos Tsitsipas at the Nitto ATP Finals

The 2020 season has been as challenging for tennis players as for the rest of the world, amid the COVID-19 pandemic. The tour was shut down for five months from March to August, and upon returning, the players had to confront several new challenges - like staying within protected bubbles, playing without fans and competing for reduced prize money.

Tsitsipas stressed that it has been a difficult time, but added that he is trying to look at the positive side of the situation.

“I'm not a person who sees the dark side of things," Tsitsipas said. "But this whole thing was very difficult to handle, to be honest with you. I'm very happy that I didn't break down, and I'm sure if you ask other players they are going to respond the same way."

“There were a few positives I can take from 2020, I had some good results. Some bad losses. Some new things that happened to me that I didn't face in the past. Some really annoying things and some beautiful things, as well. I will try and forget the negatives, because who needs negativity in this world? Just looking at the bright side of it. Trying to get to the end of the tunnel and see something better in the near future,” he added.