Both Muhannad al Balushi and Al Julanda al Kharusi suffered losses in their opening matches of the qualifying round.
While India's Vikash Thakkar routed Balushi 11-5, 11-5, 11-5, Egypt's Khalid Assar was too good for Kharusi, winning 11-4, 11-4, 11-2.
Oman's other two players in the tournament - Asad al Raisi and Haitham al Mandhari - will be in action tomorrow.
The Oman Open boasts of more than 25 players in top-100 men's world ranking. The tournament features seven categories - singles (men and women), doubles (men, women and mixed), singles U21 (men and women).
Later in the day, Slovakia’s Thomas Keinath, 41, caused a major upset and kept his hopes of main draw qualification very much alive. Listed at No 669, he beat Belgium’s Martin Allegro, ranked No 109, the second
highest rated player in qualifiers, 11-9, 16-14, 6-11, 11-13, 12-10.
There was a close call for Egypt’s Mohamed El Beiali; the fourth highest rated player in qualifiers as he beat Slovakia’s Samuel Kaluzny 6-11, 11-8, 5-11, 11-7, 11-8.
First place in the group confirmed for El-Beiali, it was the same for Pavel Platonov of Belarus and India’s Harmeet Desai; both completed the qualifiers unbeaten.
Platonov, the highest rated player in qualifying round, beat Iran’s Amir Hossein Hodaei (11-4, 11-5, 11-6); Desai, the third highest listed, accounted for Saudia Arabia’s Naif al Jadai 11-6, 11-7, 11-8.
Elsewhere, having suffered defeat in his U21 fixture, Qatar's Mohammed Abdulwahhab came back strongly in the men’s singles to beat Egypt’s Ahmed Sharafeldin 11-9, 11-9, 11-7.
In the women’s singles, Valeria Shcherbatykh got her campaign underway with a win. The Russian player took a little while to find her footing in her meeting with India’s Naina but once she found her rhythm, it was an easy path as she raced to 8-11, 11-4, 11-6, 11-2 win.