Full strength Wellington better prepared for Sydney

Four weeks and four players will make all the difference to Wellington Phoenix when it hosts Sydney FC on Sunday, coach Ernie Merrick believes.

Sydney FC's Bernie Ibini holds off Wellington Phoenix's Roy Krishna during the teams' last clash on 29 March, 2015 (AAP/SNPA) Source: AAP

When the two teams last met in late March, Wellington was missing a clutch of key players away on international duty and was pounded 3-0 at Westpac Stadium.

It went on to lose by the same scoreline to competition leader Melbourne Victory the following week, then battled to hold Melbourne City to a scoreless draw.

"Four players make a big difference," said Merrick, who also took responsibility for the big loss.

"I just felt as though I didn't remould the team without those four players."

The return of Nathan Burns, Michael McGlinchey, Michael Boxall and Louis Fenton has given Phoenix more firepower up front and extra steel at the back.

"Since the Victory game we haven't lost, and we're scoring goals again so we're getting it right," Merrick said.

Last week, trailing 0-2 until midway through the second half against lowly Central Coast Mariners, Phoenix fought back to steal a 3-2 win via a 95th minute goal to midfielder Kenny Cunningham.

Merrick is hoping the fire his team showed then will be repeated against second-ranked Sydney, who is one point ahead of fourth-placed Wellington.

Perth Glory, currently third, has been ruled out of the finals for salary cap breaches.

Merrick has made no decisions on his midfield structure for Sunday's match, but his decision last week against the Mariners to push Fenton up from left back, and to bring on Cunningham, proved crucial to the win.

"We want to be able to hold the ball in midfield, win it and hold it, and service the strikers up front," Merrick said.

"We've looked at how good we are when we get numbers in the box, and we get good service into the box.

"Sometimes it's a change of personnel, sometimes it's a change in thinking."

Merrick pointed out Wellington has lost only two games in the last 10, and says it'll need to keep that winning frame of mind against Sydney, who boasts the league's top scorer in Austrian strike Marc Janko.

"There's nothing like winning - you can't win if you don't get in the ball in the box and finish them off.

"It was good to get that happening last week, and I think that could be a crucial difference going into this game."