Milan - Top seeded Stefanos Tsitsipas shrugged off a freak hand injury to reach the Next Gen ATP Finals championship match with a 4-3 (7/3), 3-4 (5/7), 4-0, 2-4, 4-3 (7/2) win over Andrey Rublev on Friday.
Greek world number 15 Tsitsipas needed medical treatment after dropping serve in the fifth game of the decider when he angrily demolished the courtside headset that players use to communicate with their coaches.
Tsitsipas, with his pride bruised slightly more than his hand, eventually gathered himself to sweep to victory and move within one match of securing his second career title having captured his first in Stockholm last month.
"It was a rollercoaster match and I got very frustrated with all the breaks of serve I suffered," said Tsitsipas, one of the sport's most improved players having finished runner-up to Rafael Nadal in Barcelona and Toronto this season.
In Saturday's final, he will face Australian teenager Alex de Minaur after the second seed claimed a 3-4 (5/7), 4-1, 4-1, 3-4 (4/7), 4-2 victory over Spain's Jaume Munar.
De Minaur, 19, began the season at number 208 in the world rankings and reached a career-high 31 last month.
De Minaur is now an impressive 28-22 on the year after entering 2018 with just two tour-level match wins to his record.
Results from the ATP Next Gen Finals in Milan on Friday:
Stefanos Tsitsipas (GRE) bt Andrey Rublev (RUS) 4-3 (7/3), 3-4 (5/7), 4-0, 2-4, 4-3 (7/2)
Alex de Minaur (AUS) bt Jaume Munar (ESP) 3-4 (5/7), 4-1, 4-1, 3-4 (4/7) 4-2