An inexperienced Roar impressed in their 2-0 win over reigning A-League champions Sydney FC on Wednesday night.

The concluding Round of 32 saw last season's top-three A-League sides all eliminated as Perth Glory fell to Western Sydney Wanderers, and Melbourne Victory were toppled by Newcastle Jets.

Wellington Phoenix crashed out against semi-professional opponents as Brisbane Strikers triumphed on penalties, leaving just six A-League clubs in the competition.

But it was former Liverpool legend Fowler in his full-time coaching debut who grabbed all the headlines with an unexpected victory on the back of goals from Stefan Mauk and Jay O'Shea at Leichhardt Oval.

"We lined up with a 16-year-old and had an 18-year-old in the midfield so to score two goals away from home against the champions, and keep a clean sheet is an epic achievement," said Fowler.

"We had a lot of belief and were quietly confident.

"We know we still have a lot to do so we are not getting carried away."

The match was Fowler's first as a coach other than a brief stint on an interim basis with Thailand club Muangthong United in 2011.

"People mention inexperience but I'm happy and comfortable and confident in the dug-out," Fowler added.

Fowler will now be able to pit wits against former Matildas coach Alen Stajcic who is in his first full season with the Mariners.

The last-16 draw also features two former national heavyweights up against the new breed with Marconi Stallions hosting Melbourne City, and Sydney United welcoming Western Sydney Wanderers.

THE FFA CUP ROUND OF 16 DRAW

Brisbane Roar v Central Coast Mariners

Moreland Zebras v Magpies Crusaders

Adelaide Olympic v Hume City

Brisbane Strikers v Manly United

Marconi Stallions v Melbourne City

Olympic FC v Adelaide United

Edgeworth Eagles v Newcastle Jets

Sydney United v Western Sydney Wanderers

* (Home team listed first)

** Matches to be played 20-28 August

Australian Associated Press