Britain's Andy Murray lost in three sets to world number five Nikolay Davydenko in the second round of the Indian Wells event in California.
Murray is currently ranked number 44 in the world
Davydenko came out aggressively and broke the 18-year-old Scot three times in the opening set and went on to win 6-1 3-6 6-3.
Also through to the third round are top seed Roger Federer, Rafael Nadal, David Nalbandian and Andre Agassi.
But Spain's David Ferrer, the 10th seed, was the highest profile casualty.
After back-to-back wins over Andy Roddick and Lleyton Hewitt, British number one Murray lost in the quarter-finals of Memphis, the first round of Las Vegas and now in the second round of Indian Wells.
"I didn't play (my) best but I gave 100%," the Scottish baseliner said.
"I'm not going to play my best every week because I'm too young. I fought hard and he didn't make too many mistakes.
"He has some of the best groundstrokes in the game. He doesn't give away any cheap points."
World number one Federer beat Nicolas Massu of Chile in a second-set tiebreaker 6-3 7-6 (4).
"I knew beforehand it was going to be a tough match because he's been playing well," said Federer.
"He won the Olympics (in Greece) on a surface like this. I wasn't too pleased when I saw the draw because he beat me one time before (in 2002). I know he's a tough competitor and I'm happy to be through.
"I'm always worried about crashing out in the early rounds and (having) to sit here and explain why."
Spain's second seed Nadal beat Jan Hernych of the Czech Republic 6-4 6-4, while Argentina's Nalbandian, seeded four, beat USA's Justin Gimelstob 6-4 6-4.
The 19-year-old Nadal, who beat Federer to win the title in Dubai in his last tournament, struggled with the wind but was too consistent for his opponent on the day.
"It is very difficult to play like this," the Spaniard said. "It didn't feel very good. But I won and that's the most important thing."
Seventh seed Gaston Gaudio of Argentina edged past France's Cyril Saulnier, while American veteran Agassi, the eighth seed, was a 6-4 4-6 6-2 winner over countryman Paul Goldstein.
Ferrer lost 6-2 6-2 to Germany's Philipp Kohlschreiber.