Sydney FC conceded a late goal to lose 2-1 to league leader Adelaide United in an eighth-round match, following its 4-2 defeat by defending champion Brisbane, a 3-2 loss to the Melbourne Victory and a 7-2 pummeling by Central Coast.
Coach Steve Corica conceded that after a stellar 513-match career with Italian giants Juventus, Del Piero was frustrated to find himself locked in a losing streak.
Corica told reporters after Friday's defeat Del Piero was "frustrated we're losing. He hasn't lost for a long time back home in Italy.''
"We're losing games and it's not nice to lose games. He's frustrated and everybody should be frustrated,'' Corica said.
"That's football. When you're down and conceding late goals ... it's tough to take. It's just the way it's going at the moment. We've got to get on with it and find a win from somewhere.''
Midfielder Dario Vidosic scored the winner for Adelaide in the 88th minute of a match played in front of 13,317 fans in Sydney. Del Piero came close to scoring after Fabio Ferreira had given gave Adelaide a 21st-minute lead but his ambitious free kick was tipped over the bar by goalkeeper Eugene Galekovic.
Yairo Yau grabbed an equalizer for Sydney in the 57th minute, raising hopes of at least a draw but Vidosic snuffed out those hopes with his late winner.
Corica found some positive signs in a match which saw the return for Sydney of former Australia midfielder Jason Culina. Culina came off the bench in the second half to make his first A-League appearance in two years after overcoming a serious knee injury.
"It was a much better second half. We got the goal and looked likely to score the next one as well,'' Corica said. "We created chances and pressured well, they're all positives.
"But we're conceding too many goals and that's something we've got to look at.''
Adelaide coach John Kosmina also had encouraging words for his former club.
"They're a decent team and things haven't fallen for them,'' he said.
"Tonight would have hurt a lot because they did so well to get back in the game and stay in that position and created a few opportunities to maybe get something out of it.
"We killed them off at the end. When the ball doesn't roll for you, you've just got to work your way through it.''
Central Coast posted its first home win over Brisbane in 13 matches when it beat the Roar 2-1 on Sunday to stay in second place. The Mariners have lost nine times and drawn on four occasions with Brisbane in their most recent meetings at Gosford.
Teenage international Thomas Rogic scored the winner for Central Coast in the 81st minute, leaving the Mariners in second place and only two points behind Adelaide. Brisbane are second-last, just ahead of Sydney.
The Melbourne Victory, under two-time championship-winning coach Ange Postecoglou, beat Western Sydney 2-0 for its third win from four games to lift itself to third place on the league table behind Adelaide and Central Coast.
Melbourne played most of the match with 10 men after the early dismissal of young defender Sam Gallagher but took the lead with an own goal from Michael Beauchamp and sealed its win with a goal to Archie Thompson on the hour mark.
"We've got some attacking weapons going forward but we've just not been as strong defensively as a unit as we should have been in the last few games,'' Postecoglou said.
"I think apart from the first two games we're starting to show a bit of consistency and we answered a question (today) about our character.''
The Newcastle Jets rallied from 2-0 down at halftime and 3-2 in the late stages to draw 3-3 with the Melbourne Heart.
Richard Garcia scored twice for Melbourne and Josip Tadic goaled from penalty spot to give the Heart what seemed an unassailable lead. But Newcastle fought back with goals to Craig Goodwin and Ruben Zadkovic before Ryan Griffiths snatched the draw with an 87th minute penalty.
"Performance-wise this game pretty well sums us up as far as our season's concerned. We're pretty inconsistent,'' Newcastle coach Gary van Egmond said.
"The one thing for sure is that there's no way we'll be serious title challengers while we concede the number of goals we've conceded.''
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