ROTTERDAM, Feb 17 — Jannik Sinner stunned top seed Stefanos Tsitsipas in straight sets to reach the Rotterdam ATP quarter-finals on Thursday while ninth-ranked Holger Rune was knocked out by world number 160 Gijs Brouwer.

Italian 21-year-old Sinner, ranked 14 in the world and fresh from his Montpellier title last weekend, came through 6-4, 6-3.