The phrase "brilliant work" means that something is exceptionally well done or performed. It indicates that the work exceeds expectations and is impressive in its quality or success.
He could not accept the truths of the Catholic faith, but he saw its doctrines and beliefs as brilliant works of the «creative reason» of the imagination. (firstthings.com)
These guys do brilliant work in getting simple, dependable mobility into the hands of those who need it. (treehugger.com)
Many universities are already doing brilliant work to ensure more young people go on to higher education, and I would encourage this best practice to be shared across the sector. (educationbusinessuk.net)