Al Rayyan were 2-1 winners over Qatar SC, with former Villarreal striker Nilmar on target on his league bow.
Abdullah Afifa was on target after 38 minutes before the Brazilian doubled the lead in the 52nd minute.
Mohammed Razaq pulled one back for Qatar 12 minutes later but there was no equaliser.
Al Wakra defeated Al Gharafa 2-0 courtesy of Younis Mahmood's goal in the 35th minute and Yousef Eissa's strike six minutes from time.
Lekhwiya enjoyed the same scoreline against Al Siliyya, with Nam Tae-hee (13) and Sebastian Soria (26) on target.