Mikhail Biryukov and Roman Safiullin meet in the semifinal at Stuttgart on Saturday. Roman Safiullin has won 4 of the last 10. Mikhail Biryukov is 0-10 across recent matches.

The two have never played — a first meeting always adds a layer of uncertainty the numbers can't fully capture.

Hold strength tells the story — 72.7% versus 46% on first-serve points in Safiullin's favor. The edge belongs to Safiullin — real, but not the kind you take for granted at this level.