Sayyiduna Sa'd bin Abi Waqqas (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) performed one rak'ah of witr.
Imam al-Bazzar and Imam al-Tabarani in al-Mu'jam al-Awsat recorded this narration; its chain contains a narrator, Jabir al-Ju'fi, whom Sufyan al-Thawri and others declared thiqah (trustworthy), while the Imams declared him da'if (weak).