Carlos Alcaraz won only three games in his previous meeting against Rafa Nadal but after pushing the 21-time major winner to the brink on Saturday, the teenager will leave California assured he belongs at the top tier of men's tennis.

The 18-year-old Alcaraz lost 6-1, 6-2 in just 78 minutes against his fellow Spaniard when they met on clay at Madrid last year but forced Nadal to raise his level during a three hour and 12 minute slugfest in the semi-finals of Indian Wells.

Nadal, 35, prevailed 6-4, 4-6, 6-3 after an engrossing contest amid strong winds, but Alcaraz showed why he is considered the future champion of the sport.