The hosts went down fighting to Saudi Arabia 56-59, a marked improvement from its opening match defeat, when it lost to Bahrain 48-99.
A close first quarter saw both teams neck and neck with the score 12-11 in favour of Saudis.
Oman trailed 25-34 in the second and was down 37-46 in the penultimate quarter. Oman fought back strongly in the final session but was unable to avoid loss. Oman next plays UAE on Friday.
In another match, Bahrain beat UAE 84-66 to remain unbeaten.