The Reds took the lead early in the second half through an own goal before Danny Guthrie and El Zhar combined to send Ryan Flynn racing through on goal. Flynn kept his composure and scored Liverpool's second goal to wrap the game up.
"It was a good exercise and a good performance from the lads," Reserves coach Hughie McAuley told the club's official website.
"The reserve league has been cut to 18 games this season with nine home matches and nine away ones so it gives us the flexibility to play some friendly matches and keep the lads sharp.
"It was good to see the lads have listened to Gary Ablett and myself and they put the goals away to match their possession.
"It was an excellent set-up at Rangers and we were well looked after. There were a lot of positives for us to take from this game."