Dynamic fullback Matt Dufty starred with two tries and two first-half assists for Jack Bird and Mikaele Ravalawa but the scoreboard didn't quite reflect a tough contest where Parramatta struggled to execute.
St George Illawarra's goal-line and scramble defence was outstanding as they displayed line-speed and aggression from the get-go, shocking the Eels and mounting an 18-0 half-time lead.
They overcame the sin-binning of Tariq Sims early in the second half, after which the hosts finally scored, to eventually kick clear.