Stefanos Tsitsipas stunned favourite Roger Federer to reach the final on his debut at the ATP Finals on Saturday, beating the six-time champion 6-3 6-4 at the O2 Arena.
The stylish 21-year-old, the first Greek to qualify for tournament in half a century, soaked up everything Federer threw at him and returned it with interest to subdue the Swiss great.
Federer, 17 years older than his opponent, was unusually profligate when his chances came along, failing to convert his first 10 break points.
"I'm so proud of myself today, a great performance and once again the people were great," Tsitsipas said.
"I really enjoyed myself on the court and sometimes in matches like these you wonder how you recover from difficulties and break point down.
"It is a mental struggle and I'm proud how many I saved today, I was trying not to give an easy time to Roger, he was playing well.
"He was an inspiration as always. Playing him is the biggest honour I can have and today's victory is probably one of my best moments of the season. These are the moments I live for.
"I grew up watching Roger here at the ATP Finals and Wimbledon and other finals. I wished one day I could face him and today I'm here living the dream.
"I remember myself being one of the kids here watching the event and I could never picture myself here. But it can happen. Dreams can come true!"
The 20-time Grand Slam champion made a sloppy start, botching two smashes in his first service game and Tsitsipas took advantage to break with an angled forehand winner.
Federer wasted three break points when Tsitsipas served at 4-2 then lost out in a marathon 13-minute ninth game as Tsitsipas served for the first set. Tsitsipas finally bagged the opener on his seventh set point.
Looking rattled Federer dropped serve to love early in the second set but hit back immediately to finally convert a break point. Tsitsipas showed remarkable poise though, blanking out the cheers for Federer to break again with an angled forehand.
Federer looked jaded near the end and struggled to hold serve at 3-5, but at least asked the question of Tsitsipas's nerve as the Greek served for a place in Sunday's climax.
Again Federer had break points, reaching 15-40, but Tsitsipas would not be denied the biggest final of his career and hit back to finish an absorbing clash with an ace.
A year ago, Tsitsipas won the Next Gen ATP Finals. Now, on his tournament debut he is one match away from winning the season-ending event, featuring the year's best eight players.
Tsitsipas first broke into the top 100 of the ATP rankings only 25 months ago and will now face either defending champion Alexander Zverev or Dominic Thiem in the final.
