It is narrated from Sayyiduna Jabir (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) gave a verdict in favor of the claimant by taking an oath from him in the presence of one witness (as if the oath was accepted as a second witness).
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 14278