Karen Khachanov and Roman Andres Burruchaga meet in the first round at US Open on Monday. Karen Khachanov limps in on a 4-match losing skid, just 4 wins in 10. Roman Andres Burruchaga limps in on a 4-match losing skid, just 5 wins in 10.

The serve is where this match separates: Khachanov has been winning 72% of first-serve points to Burruchaga's 65.8%, and on hard that gap compounds fast. The edge belongs to Khachanov — real, but not the kind you take for granted at this level.