Heather Watson advanced to the quarter-finals of the Aegon International with a win over Flavia Pennetta she said was "the biggest" of her career.
The Briton recorded her first ever win over a top 20 opponent as she prevailed 6-7 (6-8) 6-4 6-2 in one hour and 56 minutes at Eastbourne.
Watson will meet second seed Petra Kvitova in the next round.
Johanna Konta could not join Watson in the quarter-finals, losing 1-6 7-5 7-5 to Italy's Camila Giorgi.
British number one Watson looked unlikely to win when Italian Pennetta, ranked 12th in the world, took the first set 8-6 on a tie-break.
But Watson grabbed the momentum with a decisive break in the first game of the second set, and took full advantage with some excellent serving.
The Briton cantered to victory in the third set as Pennetta struggled to cope with Watson's relentlessly accurate groundstrokes.
"I think it's probably the biggest win of my career," said Watson afterwards. "Flavia's a great player so I knew it wasn't going to be easy.
"I decided in the off-season last year that I wanted to become this more aggressive player and Diego [Veronelli, coach] agreed. We have both been working on it.
"I think aggressive is the way forward, and that's what I'm going to keep trying to do.
"Even in that first set tie-break, 4 1 up, I had a second serve. I hit it, I missed it, and you could say that was a turning point in the tie-break when I lost it, but, you know, I'm glad I went for it rather than just trying to make it; no regrets."
Konta failed to capitalise on her impressive first-round win over Belinda Bencic as she lost a topsy-turvy match to world number 42 Giorgi.
The Briton brushed aside her opponent in the first set with three consecutive breaks of serve.
But Giorgi, who beat former world number one Victoria Azarenka in the first round, came back strongly to edge the next two sets.
Both Konta and Watson will appear in the main draw of the ladies' singles at Wimbledon.
"I had a match point on her serve, and she played a flawless point. It's not much to beat myself up over really," said Konta.