Britain's Katie Boulter beat Taylor Townsend in straight sets to set up a second-round clash with world No 5 Jessica Pegula at the Mutua Madrid Open.
Boutler overcame the American 6-4 6-2 in an hour and 33 minutes to record her second career win in Madrid.
She set up 14 break point opportunities in a commanding performance against the Townsend serve, breaking four times in the match in further signs of her growth on clay.
"I feel like my confidence is building on this surface," Boulter told Laura Robson on Your Site. "I do think I'm getting stronger and believing more coming out of the corners. I think I'm improving match by match.
"I enjoy the competitive nature of this sport, which is being stubborn and not letting go or losing focus. I think that was the difference today, I dug in in the big moments, trusted my shots and then I think in the second set I stepped it up a bit and played better tennis."
Boulter beat Pegula at the 2024 United Cup, before the American levelled their head-to-head record at one apiece in the semi-finals of the Billie Jean King Cup last year.
Pegula is coming off a successful defence of her Charleston Open title having beaten Yuliia Starodubtseva 6-2 6-2.
"She's a great player, she's very in form and plays well on every surface," said Boulter. "It's going to be a massive challenge for me but I have nothing to lose at the end of the day. I can have a go at someone on a surface I don't love, and I'm going to try and play my way."
It has been confirmed that Boulter will also be uniting with 23-time singles and doubles Grand Slam champion and tennis icon Venus Williams in Madrid.
"She's an absolute icon, I'm so excited to be playing with her," said Boulter. "It's going to be a dream come true for a little girl who once looked up to her."
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