But admiration turned to disappointment on Tuesday after it was reported that the performance was mimed, not live.
Doubts about the widely-praised performance of the Star-Spangled Banner were raised after some guests sitting close to the stage on the Western Steps of the US Capitol, noticed that the award-winning singer's lips were not perfectly synchronised with the sound emerging from speakers.
The secret was apparently confirmed by the "President's Own" Marine Corps Band which had provided the backing music for the ceremony, and had themselves been accused of miming their performance.
"We performed, live, the band. But we received last-minute word that Beyoncé was going to use the pre-recorded vocal track. Those were the instructions we were given. We don't know what the reason why," Kristin DuBois, a spokeswoman for the band told the New York Post.
She added that this was standard procedure: "All music is pre-recorded for the ceremony because there are so many eventualities and conditions that day," she said.
Beyonce's New York publicist did not reply for a request for comment byThe Daily Telegraph on Tuesday, as the story exploded onto social media networks, including Facebook and Twitter, with some fans expressing dismay that the performance was pre-recorded.
Many observed that at one point during the performance Beyoncé had dramatically pulled out her earpiece, sparking a debate over whether this was part of the charade or – for the faithful – evidence that she had indeed decided to sing live after all.
While some cried "fraud", others took a more knowing approach, pointing out that Beyoncé had posted a photograph of herself in a recording studio with members of the Marine Corps band taken the day before the inauguration.
It was also recalled that during Mr Obama's first inauguration in 2009, cold weather and wind meant that recordings were used for performances by the cellist Yo-Yo Ma and violinist Itzhak Perlman.
For Conservatives, it was a chance to score political points, with the influential Drudge Report website, devoting half of its front page to a picture of Beyoncé with Barack Obama beneath the words: "Faked It!"
"This clearly means that President Obama is not really president anymore," joked one liberal commentator on Twitter, poking fun at Conservative outrage, "First scandal of a second term?", asked another.