She also insisted that fatigue was not the reason for her defeat.
This time it was the Czech Republic's Karolina Pliskova who halted the 34-year-old American, winning 6-2 7-5 to set up a final today with Angelique Kerber, who beat Caroline Wozniacki 6-4 6-3 in the other semi-final.
Czech tennis player Karolina Pliskova did something only a select few have done and that is beating both Venus and Serena Williams in the same tournament on her march in reaching the final of the US Open on Thursday.
She also becomes the first German US Open champion since Graf in 1996.
Kerber has had a magnificent year.
The 28-year-old has returned the favour in NY as her victory preserves two of Graf's long-lasting records.
Kerber, who finished 2015 ranked 10th in the world, is into her third Grand Slam final of the season after fashioning an upset win over Williams at the Australian Open in January and falling to the American in the title match at Wimbledon. Instead, Williams and Graf remain tied on both.
Karolina's career took off better than her sister's as she moved up the ranks, her best being No. 7 past year.
Heading into her semi-final having just been sent top of the rankings, Angelique Kerber confessed she found it tough to focus on her match.
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Now, she is in Saturday's final.
After being asked about it in the post-match press conference, she bluntly replied: 'I'm not talking about No 1'.
"But she was always my idol and I told her that so many times". Victories over the Williams sisters demonstrate her strength and consistency, and she has the power to push Kerber hard in the championship match. Though the German lost, she was confident that she would get another chance to prove she is the world number one.
The keys will be a sharp serve and an aggressive attack, unlike in Cincinnati where she was "just pushing the balls".
The No. 2-seeded Kerber came back to win five of the last six games after trailing by a break at 3-1 in the third set. Kerber said she was pleased with how she handled the pressure.
"It's just incredible", Kerber told Garber. "To be number one in the world, it sounds incredible". I'm not going to sit here and make an excuse, because that's not me. "Now after I can relax a little bit and try and enjoy this special night today", Kerber added.
Wozniacki, who has slipped to 74th in the rankings coming back from injuries, saluted Kerber.
In an interview after her stunning win on Thursday, Pliskova said by playing Venus earlier in the tournament in front of a crowd of nearly 23,000 fans, backing the American, had helped her prepare for her semi-final clash against Serena and the fans that supported her at the Arthur Ashe Stadium.
That comes against Pliskova, who never had been past the third round in 17 previous major appearances but became only the fourth woman to beat both Williams sisters during one Grand Slam tournament.