The opening day of the 2018 edition featured two teams that share 21 titles and it was ten-time winner Ahli-Sidab, coached by former Oman coach K K Poonacha, which took the lead in the third minute of the match through Mohammed Raheel.
India international Rupinder Pal Singh then slammed the second in the 11th minute to give Ahli-Sidab a 2-0 lead at the end of first quarter.
However, Seeb, coached by Egyptian Osama Hasnain, staged a stellar fightback as it reduced the margin just before half-time through Ismail Omar.
The third quarter had record 11-time champion Seeb go on offensive as it equalised through former Pakistan international Mohammed Dilber. Qasim Moosa's double strike put the 2016 champion ahead 4-2 with a quarter left.
Rupinder cut the deficit soon after the start of the final quarter and Rashad Salim made it 4-all in the 50th minute.
However, Seeb's Dilber opened the floodgates with three minutes left and Moosa and Owais Ahmed slammed in two goals in a space of a minute to shock Ahli-Sidab for a 7-4 win.
In a late game on Wednesday, Dhofar was up against Al Salam. Defending champion Al Nasr will begin its title defence with a game against Sohar on Thursday.
Eight teams are taking part in the tournament, which will conclude on December 17. The other teams in fray are Muscat and Salalah.
H E Sheikh Saif bin Mohammed al Shabibi, Minister of Housing, will grace the final and award the trophy.