Harrison shocks Anderson, with Cilic up next
Ryan Harrison continued the theme of shocks at the Japan Open Tennis Championships, dumping US Open finalist Kevin Anderson out in round two.
Dominic Thiem (2) and Sam Querrey (6) fell by the wayside on Tuesday, with fifth seed Anderson joining them after going down 6-3 1-6 7-6 (7-2) to Harrison.
The American made it past the second round of a tournament for the first time since July's Atlanta Open, having suffered four defeats in five matches after losing to John Isner on home soil.
Towering South African Anderson fired down 23 aces in a typically powerful display, but Harrison made inroads when it mattered most, opening up a 5-0 lead in the third-set tie-break which proved too much for his opponent to come back from.
His biggest victory in over a year will give Harrison a confidence boost, with top seed Marin Cilic awaiting in the quarter-finals.
World number five Cilic advanced to the last eight on the back of a 6-3 6-4 win over home wildcard Yasutaka Uchiyama.
David Goffin (4) and Diego Schwartzmann (8) enjoyed straight-sets wins over Feliciano Lopez and Bernard Tomic respectively.
Schwartzmann will face either Thiem's conqueror Steve Johnson or Alexandr Dolgopolov for a semi-final spot - the Ukrainian having beaten Russian up-and-comer Daniil Medvedev 6-1 6-2.
Adrian Mannarino joins Cilic, Harrison and Schwartzmann in the quarter-finals after beating Jiri Vesely 6-3 6-2.