Taylor Fritz added another scalp to his impressive Indian Wells run on Wednesday with a 6-4, 6-3 of Jannik Sinner.
With both players big baseliners, it was Fritz who took control, saving five of the eight break points he faced to take out the match.
A lengthy final rally saw the American save two points as he served out the match, pumping the air with delight after Sinner mishit a forehand shot.
He will next play either No. 3 seed Alexander Zverev or 14th seed Gael Monfils.