It is narrated from Sayyiduna Wabisah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) was asked about a man who prays alone behind the row, and he (peace and blessings be upon him) said: "He should repeat the prayer."
Hadith Referenceالمعجم الكبير للطبراني / باب الواو / 18603