Carlos Alcaraz won the battle of the 20-year-olds on Wednesday to move into the semi-final at Wimbledon for the first time.
The top seed beat the sixth seed Holger Rune 7-6, 6-4, 6-4 to set up a meeting with the third seed Daniil Medvedev - a winner in five sets over the unseeded American Christopher Eubanks.
Alcaraz and Rune have been sparring at tournaments since they were 12 - even playing doubles together during their junior careers.
"It was tough at the beginning," conceded Alcaraz after the victory. "Playing in the quarter-final at Wimbledon against someone the same age as me.
"But once you go into the court, there are no friends. You have to be focused and concentrate on yourself."
Alcaraz claimed the opening set after 65 minutes in the tiebreak. The Spaniard broke to lead 5-4 in the second and wrapped it up without fuss.
Match
Rune matched him for power, athleticism and daring but once Alcaraz engineered a break of serve in the third, the Dane could not find a way back.
Also seeking a first appearance in the semis, he showed commendable fortitude to fight off a match point but his revolt was short lived. It merely offered Alcaraz the chance to serve for the tie at 5-4.
Three match points were racked up quickly before a slight wobble. But he lifted his arms aloft in triumph when Rune mistimed the flight of a high-kicking second serve.
"It's amazing," said Alcaraz. "It's a dream to be playing in such a beautiful tournament and I'm playing at a great level on this surface. For me it is crazy."
Medvedev will test the limits of his sanity on Friday in the semi-final. The 27-year-old Russian displayed patience and solidity to withstand the bravura of Eubanks.
The world number 43, competing at this level for the first time, ripped aces past him or pummelled him with big serves.
But Medvedev, outgunned in the second and third set, waited for his chance. It came in a three-point surge during the fourth set tiebreak to take him from 3-3 to 6-3.
Eubanks' forehand volley into the net to gift Medvedev the shootout was an augur.
Medvedev, also seeking a first appearance in the last four at Wimbledon, remained solid and unruffled in the decider while Eubanks, tiring visibly, dropped away.
But what a place to fall. Court 1, Wimbledon, on a first visit.
