Rafael Nadal is one win away from clinching the year-end world No. 1 ranking. Standing in his way on Wednesday in London is Stanislas Wawrinka.

Rafael Nadal and Stanislas Wawrinka will be going head-to-head for the 12th time in their careers when they collide on the second day of Group A competition at the World Tour Finals on Wednesday night.

Nadal has won all 11 of their previous encounters, including six on hard courts. In fact, the Spaniard is 24-0 in total sets against Wawrinka and only four have progressed to tiebreakers. They have faced each other three times this season, with Nadal cruising in Madrid (6-2, 6-4), at Roland Garros (6-2, 6-3, 6-1), and most recently in Shanghai (7-6(10), 6-1).

Wawrinka’s struggles in this matchup have continued even though this has been by far the best and most consistent year of his professional life. The Swiss is 50-21 and…