Heather Watson claimed the biggest win of her career as she beat Agnieszka Radwanska 6-4 6-4 to move into the fourth round of the BNP Paribas Open.
Watson had never beaten a top-10 player before and had lost to Radwanska at Indian Wells last year but broke the seventh seed five times on her way to victory in an hour and 33 minutes.
Victory in Hobart in January had given Watson the second title of her career and the world No.43 will now take on either Carla Suarez Navarro or Anastasia Pavlyuchenkova in the last-16 in California.
The 22-year-old had not won a set against Radwanska in three previous WTA meetings but broke in the first game on her second break point and then held her save to take a 2-0 lead.
Radwanska held and then broke back but Watson was giving her opponent some serious trouble and once again claimed the advantage on a fourth break point.
The rest of the set went with serve but it was Radwanska who was being made to work the harder and Watson closed out with an ace.
Watson needed just one break point to again take the early advantage in the second set and she then held her serve again although Radwanska won the third game to love.
The Pole seemed to have found some rhythm and just as in the first set broke back for 2-2, although she required three break points to do so.
Radwanska was beginning to build up a head of steam now and eased through her next service game before breaking Watson to make it four games in a row.
The match looked to be swinging Radwanska’s way but Watson halted her momentum by getting back on serve and seeing off two break points for an impressive hold to make it 4-4.
The momentum was now back with Watson and she won the next on a second break point before serving out to love to take the match.
“Aga is a fantastic player,” Watson told BT Sport 2. “I’ve played her quite a few times and she’s beaten me pretty comfortably every single time so I knew I was going to have to bring my A-game and play my very best and that’s what I did.
“The crowd definitely helped me today. I absolutely love it here. What’s not to love? For three years I didn’t win a match here and then last year I won a couple and here I’ve won a few more so hopefully I can keep it going.”
Elsewhere, tenth seed Lucie Safarova was beaten 7-6(5) 7-5 by Elina Svitolina in little under two hours on court.