The 21-year-old filled a Rafael Nadal-sized void at Roland Garros with a marathon 6-3 2-6 5-7 6-1 6-2 victory in four hours and 19 minutes.Fourth seed Zverev had sent old warrior Nadal out on his shield for probably the last time in the first round.But young pretender Alcaraz vanquished the German to join fellow Spaniard Nadal as the only men to lift the Roland Garros trophy aged under 22.Alcaraz is also the youngest man to win a grand-slam title on all three surfaces, adding the Paris clay to his hard-court US Open success and last year’s win on the Wimbledon grass.He boasts a perfect…