A spot in the next round is at stake on Tuesday, when J J Wolf goes up against Ze Zhang in the Vancouver round of 32. Ze Zhang comes in at 5 wins from the last ten. J J Wolf has won 2 of the last 10.

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

Neither the serve numbers nor the ratings separate these two by much, which is why our number stays close to even. The edge belongs to Zhang — real, but not the kind you take for granted at this level.