The FFA Cup began with a flurry of goals across Tuesday's four games with former national champions Sydney Olympic and Brisbane Strikers both securing come-from-behind wins.

There was no such joy for Melbourne Knights, two-time champions of the defunct National Soccer League, who crashed to a 3-1 defeat against Olympic FC in Brisbane.

The new national knockout cup - styled on England's FA Cup - opened with the spotlight on the nation's semi-professional ranks.

The A-League clubs will enter the fray over coming weeks.

Sydney Olympic, NSL champions in 1990 and 2002, turned on the style in the second half for a 3-1 win at Manly United.

Former Sydney FC and Newcastle Jets striker Chris Payne netted early on for Manly. However, Olympic eventually found their rhythm on Cromer Park's artificial surface to run out deserved victors.

Brisbane were pushed all the way by nine-man underdogs Broadmeadow Magic in Newcastle before hitting the lead in extra time with a winner from the boot of full-back Scot Coulson.

Broadmeadow lost their skipper Josh Piddington to a red card with eight minutes of normal time remaining for a last-man foul, while goalkeeper Chris Bowling saw red during extra time.

Earlier, prolific Strikers forward Matt Thurtell cancelled out Scott Pettit's opener, while Keenan Duimpies missed a penalty for the visitors.