Britain's Andrew Murray cruised into the last four of the French Open boys' singles with a 6-4 6-2 win over Juan Martin Del Potro of Argentina.
Top seed Murray, who won the US Open last year, claimed a decisive break towards the end of the first set before racing into a 3-0 lead in the second.
Del Potro broke back for 3-1 as Murray, 18, struggled with his serve.
But the Scot broke back immediately, losing only one more game as he earned a semi-final against Marin Cilic.