The Nigeria Professional Football League champions only needed goals in the first half from Kazie Enyinnaya, Paul Acquah, a brace from Ebube Duru, and an incredible shot from Malachi Ohawume to defeat their opponents at the Adokiye Amiesimaka Stadium.
Rivers United started off on a fast note and were quickly awarded a penalty just 11 minutes into the contest.
Paul Acquah was brought down in the box by Al Nasr’s goalkeeper who later got booked for the challenge and Ebube Duru stepped up, colly converted the spot kick to give the home side the lead.
Two minutes later, found themselves 2-0 up as Kazie Enyinnaya quickly doubled the lead for Wike Boys.
20 minutes into the game, Nyima Nwagua came close to making it three but tipped his shot just over the post before Chibuzor Ohawume shoots from range and narrowly missed the target as well.
14 minutes later, the Stanley Eguma side thought they’ve grabbed the third goal, only for Joseph Onoja to miss from inside the six yards box as his strike narrowly went inches wide.
The Port Harcourt outfit went all out in search of more goals, four minutes before the interval, Paul Acquah finds back of the net to increase the lead to 3-0 and it ended that way into the first half break.
The Pride of Rivers kicked off the second half same way they started the first and barely three minutes in, Nyima Nwagua pulls a diving header on Ebube Duru’s Cross only to watch his effort come off the woodwork.
63 minutes on, Rivers United were awarded yet another penalty in the game and Ebube Duru converts yet again from the penalty spot to double his tally and make the scoreline 4-0.
9 minutes later, Malachi Ohawume makes it 5-0 for Rivers United with a thunderbolt strike at the back of Al Nasr net to seal off the win.
Next week Wednesday is set aside for the second leg match; the victor advances to the group round.