Germany's highly-tipped Sabine Lisicki moved into the fourth round at Wimbledon on Saturday with a 6-2, 6-4 win over Japanese qualifier Misaki Doi.
Wildcard Lisicki, who knocked out French Open winner Li Na, the fourth seed, in round two, was too good for Doi, who has impressed on her debut at the All England Club.
Lisicki faces Petra Cetkovska of the Czech Republic for a place in the quarter-finals.
Doi, 20, ranked 133 in the world, defeated US 30th seed Bethanie Mattek-Sands in the first round and followed it up by knocking out China's 2008 Wimbledon semi-finalist Zheng Jie.
The left-hander has spent most of her brief career playing events below the main tour on the ITF Circuit, but she has risen to the occasion magnificently in just her second Grand Slam.
Power-packed Sabine Lisicki, a 2009 Wimbledon quarter-finalist, regularly serves at more than 120 miles (190 kilometres) per hour.
Last year a serious ankle injury left her sidelined for four months and struggling around on crutches. Her ranking slumped to 218.
Last month her French Open campaign ended in tears when she was stretchered off court with another injury when playing Vera Zvonareva.
Her ranking has plummeted so badly that the 21-year-old needed a wildcard to get into the Wimbledon main draw.
The organisers' decision was vindicated when the Florida resident, who was world number 22 when disaster struck, saved two match points to dump Li out of this year's tournament.
Lisicki won the Wimbledon warm-up event at Birmingham last week to illustrate her grasscourt credentials and her world ranking has now risen to 62.