British number one Johanna Konta went out of the Madrid Open in the second round, losing to Romanian world number three Simona Halep.
Two-time Madrid champion Halep, 27, wrapped up a 7-5 6-1 win in one hour and 30 minutes.
On Sunday, world number 47 Konta, 27, lost the Morocco Open title to Maria Sakkari in her first final on clay.
Halep, who won the Madrid title in 2016 and 2017, will play Slovakia's Viktoria Kuzmova in the third round.
"I feel like I started playing at a really good level," Konta told BBC Sport.
"I thought I found my footing reasonably quickly. As you would expect playing against someone like Simona, she's going to rally back and what she does incredibly well is compete and really work her way into the points.
"I definitely created chances in that first set - unfortunately I couldn't capitalise. And then I think I just ran out of a little bit of steam there in the second set."
Konta was the first to go up a break, leading 2-1 before easing through two service games to take a 4-2 lead.
She found herself at break point to reach 5-2 but Halep managed to hold serve, going on to break Konta to level the scores.
At 5-5, Halep withstood three break points and when leading 6-5, managed to wrap up the set on her fifth set point.
The French Open champion asserted her dominance in the second set, allowing Konta only two points in the first four games.
Konta broke her opponent's serve to get a game on the board, but Halep broke back immediately before serving out the match.