Saeed bin Jubair said that Ibn Abbas told him: He (the Prophet) got up and prayed eight rak'ahs in pairs, and then observed witr with five rak'ahs and he did not sit between them.
Hadith ReferenceSunan Abi Dawud / Prayer (Abwab Qiyam ul Lail) / Hadith: 1358
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:إسناده صحيح