Heather Watson claimed the scalp of a player ranked 104 places above her to reach the third round of the Miami Masters - where she will next face world No.1 Victoria Azarenka.
Watson, 19, followed up her fine comeback victory over Sorana Cirstea in the first round with an even more impressive 6-2 6-1 triumph over world number 25 Lucie Safarova on Friday.
Watson dominated throughout in both defence and attack and her Czech opponent had no answers with the Guernsey player wrapping up her second-round victory in little more than 80 minutes.
Watson won 73 per cent of points on her first serve, in contrast to Safarova's 46 per cent, while serving two aces and staved off six of the seven break points she faced.
Watson opened the match and successfully held before breaking 27th seed Safarova in her first service game and then holding to move into a 3-0 lead.
Safarova held for 3-1 and then moved to break point, which she failed to convert with the Briton taking full advantage.
Azarenka next
Watson then forced three break points in the sixth game but failed to convert them and Safarova eventually held for 4-2.
Watson held and then broke her opponent to take the first set 6-2.
The first game of the second set saw the pair trade break point chances with the Czech player eventually prevailing.
Florida-based Watson though immediately broke back and from then there was no stopping the Guernsey-born player.
She will next face top-seed Azarenka in what will be a repeat of the Australian Open first round meeting earlier this year.
The Belarusian ace was handed one of her toughest tests so far this season before overcoming Holland's Michaella Krajicek 6-3 7-5.
Venus Williams claimed a stunning three-set win over Wimbledon champion Petra Kvitova as her comeback gathered momentum.
The 31-year-old has been absent from the WTA Tour since pulling out of the US Open at the end of August, remaining sidelined with Sjogren's syndrome, a disorder of the immune system, until this week. She has fallen to 134th in the world rankings as a result.
Positive
But the seven-time former grand slam winner made a positive return by knocking out Kimiko Date-Krumm in round one - and she rolled back the years in knocking out world No.3 Kvitova.
Williams, a three-time former winner of this tournament, won 6-4 4-6 6-0 in two hours and 18 minutes to march through to the last 32, where Canadian Aleksandra Wozniak awaits her after a 4-6 6-3 6-4 success over Romanian 28th seed Monica Niculescu.
It was a day otherwise full of surprises as Spanish wild card Garbine Muguruza Blanco ousted ninth-seeded Vera Zvonareva 6-4 6-3.
The Russian's fellow seeds Angelique Kerber, Monica Niculescu and Kaia Kanepi also bowed out at the hands of Zheng Jie, Aleksandra Wozniak and Silvia Soler-Espinosa respectively.
There were no such troubles for the 15th-seeded Ana Ivanovic of Serbia, who won 6-4 7-5 against Vania King of the United States, while Slovakian 16th seed Dominika Cibulkova was a 7-5 6-1 victor against Anna Tatishvili of Georgia.
