The 18-year-old Alcaraz is aiming for his third title of the season after he won at Rio de Janeiro in February and in Miami this month. Alcaraz called it his biggest win on clay. “Unbelievable game that I played, unbelievable atmosphere that I lived today on court. It was unbelievable everything,” the precocious talent who is drawing comparisons to a young Nadal said.

“The atmosphere here, the crowd, the level that I played, the level of the match. It was incredible.” All of the players who reached the quarterfinals had already played third-round matches earlier on Friday that had been pushed back from Thursday due to rain delays.

Before facing Alcaraz, Tsitsipas needed just over an hour to beat Grigor Dimitrov 6-1, 6-4. Alcaraz similarly eased past fellow countryman Jaume Munar 6-3, 6-3. Tsitispas looked finished when he was trailing Alcaraz by a set and 4-1.

He fought to pull level with the youngster, but Alcaraz dominated the third set. The teen sensation won the nighttime crowd over with his wide range of winners, including several well-placed drop shots that Tsitispas failed to reach.

Alcaraz, ranked 11th, is guaranteed to move into the top 10 men's rankings. Alcaraz will face Alex de Minuar on Saturday after the Australian beat fourth-seeded Cameron Norrie 6-3, 5-7, 6-1. Tsitsipas, who won Monte Carlo last weekend, was trying to reach his second straight final in Barcelona. Instead, his record against Alcaraz is now 0-3.

On the other side of the bracket, Pablo Carreno will meet Diego Schwartzman after both produced comebacks. Carreno fended off three match points in the second set and came back from a break down in the third to overcome second-seeded Casper Ruud 4-6, 7-6 (8), 6-3, in three hours.

Schwartzman came back to beat third-seeded Felix Auger-Aliassime 3-6, 6-2, 6-3.