The reigning cup winners proved too strong for Paul Reid's NPL NSW club Rockdale City Suns, triumphing 4-2.

The Suns had gone ahead early through Gaitatzis, but Sydney responded emphatically with the next four goals at Illinden Sports Centre.

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Adelaide's new signings Mirko Boland and Craig Goodwin were both on the scoresheet as the Reds eased past Central Coast 3-0 at Marden Sports Complex.

The Mariners, who were remarkably playing their first game in pre-season, bow out in the Round of 32 for the fourth straight season.

Elsewhere, NPL Queensland club Cairns FC were too good for NPL WA club Armadale 4-0, while Heidelberg United made the last 16 again with a 2-1 win over Charlestown City Blues.

Rockdale City 2 (Gaitatzis 6', Alameddine 76') Sydney FC 4 (De Silva 30', Warland 48', Brosque 51', 64'), Illinden Sports Centre

Ex-Juventus trialist Harris Gaitatzis lobbed home an early goal for Rockdale which left Sydney stunned, but new recruit Daniel De Silva stepped up with a fine volleyed strike on the half hour mark.

Ben Warland put Sydney ahead before veteran skipper Alex Brosque hit a brace to ease any concerns. Toufic Alameddine grabbed a late consolation for the Suns.

Heidelberg United 2 (Davison og 1', Ellis 13') Charlestown City Blues 1 (Ott 82'), Olympic Village

The NPL Victorian club raced to an early two-goal lead to set up the victory. Daniel Ott fired in a superb strike from outside the box for a consolation for the NPL Northern NSW side.