Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) stated that the person against whom a claim is made has the right to take only an oath; however, if evidence is presented (then the ruling will be different).
Hadith Referenceسنن الدارقطني / كتاب فى الأقضية والأحكام وغير ذلك / 4511
Hadith Takhrij«أخرجه الدارقطني فى ((سننه)) برقم: 4511 ، انفرد به المصنف من هذا الطريق»