Serena Williams is wondering when she will start playing like a 23-time Grand Slam champion again in a major final, calling her poor showing in Saturday's US Open final loss "inexcusable." Williams fell to 19-year-old Canadian Bianca Andreescu 6-3, 7-5 at Arthur Ashe Stadium on the same court where she won her first Grand Slam title 20 years ago, nine months before Andreescu was born. "I love Bianca. I think she's a great girl. But I think this was the worst match I've played all tournament. It's hard to know that you could do better," Williams said. "Bianca obviously played well. I think her returns make me play better and put pressure on my serve.

"At the same time it's inexcusable for me to play at that level." Williams had 33 winners but just as many unforced errors. She hit nine aces but misfired eight double faults and hit only 44 percent of her first serves. She dropped 30 of 43 points on her second serve. "I believe I could have played better. I believe I could have done more. I believe I could have just been more Serena today," Williams said. "I honestly don't think Serena showed up. I have to kind of figure out how to get her to show up in Grand Slam finals." Williams, who remains one Slam title shy of matching Margaret Court's all-time record, has lost the past two Wimbledon and US Open finals since returning after having a baby two years ago.