Trio of A-League contenders flex muscles

Adelaide United coach Josep Gombau warned his players to be wary after humbling Perth Glory in a round when A-League contenders flexed their muscles.

Adelaide dismantled the Glory 2-0 on Sunday to join Melbourne Victory and Sydney FC as the league's unbeaten sides.

The trio banked round three victories - as did rising Wellington Phoenix, now perched in fourth after a 4-1 Sunday feast of Newcastle Jets.

Adelaide's Gombau desperately tried to keep a lid on his side's scalping of Perth, who started the round as ladder leaders yet finished the weekend in fifth.

"We are happy ... the team is doing well," Gombau said after a victory featuring a third goal in as many matches to Spanish star Sergio Cirio.

"But what I want is week by week. And be careful, because sometimes when you think you are playing well, the next game you lose."

After the Phoenix, with Nathan Burns scoring twice in Wellington against the Jets, logged a second triumph from three starts, a smooth Adelaide extended their daunting unbeaten record at home to 11 games.

Third-placed Adelaide have two wins and last weekend's draw against Melbourne Victory, who top the table after an ominous 5-2 belting of home town rivals Melbourne City on Saturday night.

Trump recruit Beshart Berisha scored a hat-trick and stalwart Archie Thompson netted twice to leave their hard-nosed coach Kevin Muscat in awe.

"There was a trail of smoke following that ball, it was that hot," Muscat said.

City, with two losses and a draw, have conceded seven goals this season and faded in the second half - they were 2-2 at halftime.

"We should analyse why ... because in the second half, games get decided. It's something we must improve," City coach John van 't Schip said.

Improvement is something Brisbane Roar coach Mike Mulvey is demanding of his title holders who on Friday night slipped to a 0-2 loss to Sydney FC, now in second spot with two wins and a draw.

The Roar have become the first defending champion, and just the second club ever, to open an A-League season with three consecutive losses.

"We'll have a look at everything. We need to regroup," Mulvey said after the Roar joined now-defunct North Queensland Fury, in 2009/10, as the only clubs to start a campaign with three defeats.