Melbourne Victory will face Adelaide United in the next round while the Wanderers meet Perth Glory.
Hume City meet Oakleigh Cannons while Heidelberg United face Melbourne City in the other quarter finals.
Hume City 3 (Ingham 34’, Schroen 42, Markelis 83’)
Sydney Olympic 1 (Hatzimouratis 63’)
Hume City booked a place in the FFA Cup quarter-finals courtesy of a comprehensive 3-1 victory at home to Sydney Olympic on Tuesday night.
The hosts took the lead at ABD Stadium in the 34th minute when Jai Ingham's driving run and shot was only parried by goalkeeper Paul Henderson, Daniel Clark arriving to poke home the rebound.
Hume doubled their advantage three minutes before the break, Nick Hegarty advancing down the left flank and finding Marcus Shroen in the middle of the penalty area for the midfielder to tuck home a simple finish.
The visitors from New South Wales refused to give up without a fight, Dimtri Hatzimouratis seizing on a rebound to beat Chris Oldfield from the edge of the area in the 63rd minute.
The result was put beyond doubt though with seven minutes to go when Shaun Timmins found space down the right and cut the ball back to Theo Markelis, who dispatched an emphatic strike past Henderson, sending the Victorian outfit into the quarter-finals.
Rockdale City Suns 2 (Jesic 53’, Broxham OG 86’)
Melbourne Victory 3 (Berisha 45’, 50’, Makarounas 65’)
Melbourne Victory avoided what would have been a huge upset by holding off a gallant Rockdale City Suns to win 3-2 away from home in a memorable FFA Cup round-of-16 encounter on Tuesday night.
A first half of stout resistance and no little enterprise from Rockdale at Kogarah Oval was broken a minute before half-time when Daniel Georgievski exchanged a neat one-two with Fahid Ben Khalfallah before bursting into the penalty area and getting the ball to Jesse Makarounas, who picked out the far corner of the net expertly.
The visitors made it 2-0 five minutes into the second half following a well-worked move from a set-piece, Ben Khalfallah's scooped pass finding the head of Besart Berisha, who made no mistake from close range.
The Suns got one back from the penalty spot on 53 minutes, Marko Jesic stroking the ball home from the spot after Jason Geria was penalised - perhaps somewhat harshly - for handball.
The hosts' hopes of a comeback took a big blow in the 65th minute when Makarounas curled home another well-taken finish from just outside the area, the attacker completing his brace and restoring Victory's two-goal advantage.
The team coached by former A-League player Paul Reid refused to lie down, Nicholas Petrillo heading a deep corner back across goal and Leigh Broxham turning it into his own net to make it a nervy last four minutes for the league champions.
MetroStars 0
Oakleigh Cannons 1 (Pavlovic 66’)
A well-taken goal by Mirjan Pavlovic midway through the second half proved enough for Oakleigh Cannons to progress to the FFA Cup quarter-finals at the expense of MetroStars.
With a strong breeze at their backs at Elite Systems Football Centre it was the home side that dominated the first half arm-wrestle, but they were unable to turn their dominance into a goal.
Winger Rocky Callisto went closest to breaking the deadlock before the break, his close-range header superb clawed away by Cannons ‘keeper Lajos Hun.
Whatever Arthur Papas said to his side at half-time worked as they Cannons came out breathing fire, with Pavlovic and Dean Piemonte both squandering great chances.
But the breakthrough came on 66 minutes after shocking error by experienced MetroStars ‘keeper Daniel Godley.
The gloveman came racing out of his box to deal with a hopeful long-ball but it bounced over his head, allowing ex-Hyundai A-League attacker Pavlovic to race onto it and slam it home from a tight angle.
Despite a frenetic finish as the home side pushed for an equalizer, the Cannons held on for a superb victory much to the delight of the travelling fans on a fantastic night for the Melbourne club.
Palm Beach Sharks 0
Western Sydney Wanderers 2 (Delgado 26’, Hamill 86’)
The A-League powerhouse ended the Sharks’ FFA Cup run with a solid 2-0 win at Cbus Stadium on the Gold Coast.
The Sharks started confidently but Wanderers settled and soon eased past the Sharks. New signing Mitch Nichols released Sotirio on the right side of the box, and the youngster shimmied then crossed to the far post for Delgado to head home unmarked on debut.
Federico Piovaccari and Nichols had efforts on goal but the visitors weren’t able to add to their tally by the break.
Brendon Santalab came on in the second half for Piovaccari while another substitute Josh McDonald came close to making it 2-0 in a tight second half.
Jack Boxell, last year’s Cup hero for the Sharks, was introduced as the home side stepped up their efforts to equalise in front of the almost 1800 fans.
But in the final minutes Wanderers saw off the Sharks with a second after a corner wasn’t cleared and Brendan Hamill guided it home low past the keeper to make it 2-0 and book the red and black an FFA Cup quarter-final spot.