Brisbane - Eighth seed Madison Keys led a trio of Americans through to the quarter-finals of the Brisbane International with an impressive win over Australia's Samantha Stosur on Wednesday.
Keys beat the former US Open champion 7-5, 6-3 to reach the last eight, her best result at the Brisbane International in four attempts.
She will play fellow American Danielle Collins in the quarters after Collins thrashed Kazakh qualifier Yulia Putintseva 6-1, 6-0 to continue her blistering start to the season.
Collins demolished world number five Elina Svitolina 6-1, 6-1 in the first round and has lost only three games in two matches, spending just 114 minutes on court over two rounds.
"It's going to be tough," Keys said of her quarter-final opponent.
"She's playing incredibly well and really ripping and going for shots and she's making pretty much all of them right now."
The third American through on a day when only three singles matches were played was Alison Riske, who downed Czech Barbora Strycova 6-3, 6-4.
Riske will take on either second seed Karolina Pliskova of the Czech Republic or Australia's Ajla Tomljanovic in the quarter-finals.
Pliskova and top seed and world No 1 Ash Barty, who had opening round byes, play their first matches on Thursday.
Results from matches played on the third day of the Brisbane International at the Queensland Tennis Centre on Wednesday (X denote seed):
Alison Riske (USA) bt Barbora Strycova (CZE) 6-3, 6-4
Danielle Collins (USA) bt Yulia Putintseva (KAZ) 6-1, 6-0
Madison Keys (USA X8) bt Samantha Stosur (AUS) 7-5, 6-3