The Hello hitmaker, who swept music's big night by winning all five honours she was nominated for, was invited to celebrate George's legacy onstage at Los Angeles' Staples Center with a reworked version of his 1996 hit Fastlove.
However, Adele was left close to tears after struggling with sound issues seconds into the segment, and stunned audience members and viewers alike by abruptly halting the live set and asking to start again, insisting, "I'm sorry, I can't mess this up for him."
She also let slip an expletive during the unexpected break, which was censored for the TV broadcast, prompting her to apologise profusely onstage.
Her second attempt was pitch perfect, earning her a standing ovation from the star-studded crowd, but Adele was still heartbroken by the false start as she spoke to reporters backstage after the prizegiving.
The British singer admitted her run-through for the show hadn't gone quite as planned earlier in the day, but she was hopeful her hard work would pay off.
"I was devastated by that (having to restart), and my rehearsal - I did have a shaky rehearsal," she confessed. "But I have been working very hard on this tribute for him, every day."
Adele also explained she was so nervous about the set because she was a huge admirer of George's talents: "I found him to be one of the truest icons," she said.
Meanwhile, the tribute wasn't Adele's only mishap during the ceremony - she also broke her Grammy Award for Album of the Year in half while onstage at the end of the night.
The star was photographed holding the two pieces of the gold gramophone prize after dedicating the honour to her category rival and pop icon Beyonce, but it's not clear if the act was deliberate or just an accident.
The broken award was promptly replaced so Adele could pose with all five of her accolades intact backstage.
Adele admitted even she was hoping the pregnant superstar would win the coveted Album of the Year award for Lemonade, which she praised onstage as "monumental".
"A piece of me did die inside as a Beyonce stan (super fan)," she told the media. "I'm not going to lie, 'cause I was completely rooting for her - I voted for her."
"I thought it was her year," she added. "What the f**k does she have to do to win Album of the Year?"