The all-female a cappella group were sent home from the competition on Monday night after landing in the bottom two alongside Afro-Blue following a night where the groups performed one rock track and one country song.
Delilah had chosen Aerosmith's 'Dream On' for their rock track, which saw member Amy Whitcomb praised by judges Shawn Stockman, Ben Folds and Sara Bareilles for her lead vocals.
Shawn said that he saw a "female Steven Tyler" on stage, while Sara said she had a "rare female voice that really translates to rock music well".
However, both Ben and Sara suggested that despite giving a technically great performance, perhaps the group had reached their peak too early in the song which left them with nowhere to go.
For their country track the group chose 'If I Die Young' from The Band Perry which saw Ingrid Andress praised by all three judges for her opening vocals.
However, while the panel thought the group put a lot of emotion and heart into the performance, they also pointed out a few pitch issues.
Speaking after the result was announced, group member Hannah Juliano said: "We really are just so amazingly blessed to have been back here at all.
"We have found something very special in each other and this group. We really hope we have instilled some kind of feeling in the people we are singing to. Thank you so much for your love and support - we really appreciate it."
Delilah was formed from contestants who appeared on the first two seasons of The Sing-Off and then some additional members.
They chose 'Survivor' by Destiny's Child as their swansong.
Delilah's departure means that just five groups will continue in the competition to win the $200,000 cash prize and a recording contract with Sony Music.
The remaining groups and the songs they chose this week are:
Pentatonix - 'Born To Be Wild' by Steppenwolf / 'Stuck Like Glue' by Sugarland
Dartmouth Aires -'We're Not Going To Take It' by Twisted Sister / 'Save A Horse (Ride A Cowboy)' - Big and Rich
Afro-Blue -'American Girl' by Tom Petty and the Heartbreakers / 'Need You Now' by Lady Antebellum
Urban Method - 'Here I Go Again' by Whitesnake / 'Before He Cheats' by Carrie Underwood
Vocal Point - 'You Really Got Me' by The Kinks / 'Life Is A Highway' by Rascal Flatts
The Sing-Off airs Mondays at 8/7c on NBC
> Read Digital Spy's full Sing-Off headlines
Watch Delilah's swansong below: