For a place in the final, Alcaraz will face Friday - the day of his twenty years - the Croatian Borna Coric (20th) or the German Daniel Altmaier (92nd and lucky loser).
In the eighth-finals on Tuesday, "Carlitos" had left only three games to Alexander Zverev, former world N.2 now 16th. On Wednesday afternoon, Khachanov made it much more difficult for him.
In the second set, the Russian even served for the set, at 5 games to 3, but Alcaraz avoided a third set by winning this game and the next three, to win in just under two hours.
"Winning this match gives me a lot of confidence, Karen played at a very high level, he pushed me to my limits," he said.
Titled on ochre in Buenos Aires in February and then in Barcelona ten days ago, the protégé of Juan-Carlos Ferrero now has an almost perfect record on clay in 2023, with 17 wins for only one defeat (in the final of the Rio de Janeiro tournament against the British Cameron Norrie at the end of February).
Carlos Alcaraz on May 3, 2023 during his quarterfinal victory at the Masters 1000 in Madrid against Russia's Karen Khachanov. The Spaniard is 17 wins to only one defeat this season on clay © Thomas COEX / AFP / Archives
In the absence of Rafael Nadal and Novak Djokovic, Alcaraz is the favorite in the Spanish capital.
© 2023 AFP