Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) says: "Yawning and sneezing during the prayer are from Satan."
Tabarani recorded it in al-Mu'jam al-Kabir, and its narrators have been declared trustworthy. Further on, a narration from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) about dozing during the prayer will come; it will come in the chapter on Surah Al Imran, if Allah wills.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الصلاة / 2472