Simona Halep said she was not in a "good mood" as she lost to Mirjana Lucic-Baroni at the U.S. Open.
Halep, seeded two at Flushing Meadows, lost 7-6 (8-6), 6-2 to Lucic-Baroni, a Croatian veteran who reached the past 16 at a tennis grand slam for the first time in 15 years. She reached the Open's fourth round and at least the quarters at all three grand slams before this week.
Halep credited Lucic-Baroni for her momentous victory, despite blowing a 5-2 advantage in the first set -- and three points on serve to take the opener in the eighth game.
"She played really well today. I mean, after I had 5-2 and the two [three] set points, she came back really well and she started to hit every ball," Halep said.
"Everything was in for her. It wasn't my best day, but still I did everything I could on court.
"She was better than me today, so I have to just to keep working every day hard and to look forward for the next one."
Halep is the Open's biggest upset victim to date.
Lucic-Baroni will face Italian 13th seed Sara Errani for a spot in the quarterfinals. Errani advanced with a three-set victory over Venus Williams, who also blew her match despite a big early edge and a chance to win before a tiebreaker finish.