The Wellington Phoenix's hopes of taking a potentially settled squad into the last two games of the A-League soccer season ahead of the playoffs have been dealt a blow.

There will be enforced changes to the backline for Wedesday's away match against Sydney.

Inspirational skipper Andrew Durante is under suspension for the last two matches - the final game is at home on Sunday against North Queensland Fury - after earning his eighth caution of the season during Saturday's crucial 1-0 away win over Adelaide United which consolidated their spot in the top six.

Coach Ricki Herbert will also be without defender Ben Sigmund and midfielder Manny Muscat who are already suspended for the Sydney encounter.

Midfielder Vinnie Lia also picked up a hamstring injury from the Adelaide match and is not expected to be fit to play on Wednesday.

Herbert may have to use an untested combination of Jade North and James Musa in the heart of the defence while club veteran Daniel may get more game time in midfield in place of Lia with Leo Bertos still sidelined by a groin problem on Wednesday.

Meanwhile striker Chris Greenacre is still celebrating his 34th minute strike with a diving header which gave the Phoenix their win over Adelaide.

It was Greenacre's 13th goal for the Phoenix and the first time he had scored the winning goal for his club.

"It's always nice to score, and I know every goal is important but there is nothing better for a striker than to get the winner," Greenacre said.

"It was a great cross from Marco (Rojas). As soon as he got the ball I was desperate to get into the box because his crosses are quality and this one was inch perfect.

"Marco has been outstanding since he came into the side. He has won us games with his crosses and scored a couple himself.

"We created some good chances and the fact we only scored one was down to the brilliance of Eugene Galekovic.

"He is rated the best keeper in the league and he showed it. One save in particular, from Nicky Ward, was amazing."

The most frightening moment for the Phoenix, fighting desperately for only its second away win of the season and its first ever in Adelaide, came late in the piece when Jade North miscued a clearance and thundered the ball against his own crossbar.

"When the ball came back off the bar I knew we were going to win," Greenacre said.