Spain's world number one Carlos Alcaraz defeated American Tommy Paul in straight sets to reach the quarter-finals of the Miami Open.
The 19-year-old US Open champion won 6-4 6-4 to extend his winning streak to nine matches.
Alcaraz must defend his title in Miami in order to stay atop the ATP rankings.
He will play another American, Taylor Fritz, in the last eight after the ninth seed beat Denmark's Holger Rune 6-3 6-4.
Tournament victory would also see him achieve the rare 'Sunshine Double' following his title win at Indian Wells earlier in March.
Elsewhere, Russian Karen Khachanov recorded his first victory over second seed Stefanos Tsitsipas, beating the Greek 7-6 (7-4) 6-4.