Carlos Alcaraz is the 20-year-old standing between Novak Djokovic and a record 23 grand slam titles
So studiously have Carlos Alcaraz and Novak Djokovic avoided each other that there is an element of Coe versus Ovett about Friday's French Open semi-final.
But now the match that everyone has wanted to see is finally here, and it is not just the clash of the year to date but an encounter that could yet define this and coming seasons.
The two great middle distance runners only met six times in their whole careers, and the same scarcity value applies to another pair of great athletes, the worlds two best tennis players at present.
It is a curiosity that they have only faced each other once before, which was when a deciding tiebreak saw the 20 year-old Alcaraz in last years Madrid Open, played at the slight altitude of the Spanish capital.
This is largely explained by injuries suffered by the Spaniard after he won the US Open, and also the ban on entering the United States (now expired) which Djokovic was prepared to suffer as a price of not being vaccinated against Covid. They have only been at the same tournament once this year, last months Italian Open.