Such tactics from the Wanderers invited the Phoenix in to the game, particularly during the second spell, as the home side began to slowly enjoy the run of the race but they couldn't find a winning goal.
Merrick went to his bench around the hour mark as he looked to inject some pace and creativity in to the game through the likes of Paul Ifill and Tyler Boyd.
Despite being on the back foot for much of the second spell, Wanderers forward Mark Bridge had a golden chance to collect the points in the 77th minute but sprayed his shot well over the bar.
Minutes later, Phoenix striker Boyd had a clear shot of his own but only stung the palms of Wanderers custodian Ante Covic who made a comfortable save and he was again tested shortly after as Ifill hit a strong shot in Covic's direction but the goalkeeper was up to the task.
The best chance of the game for Wellington came in the opening spell.
Phoenix midfielder Carlos Hernandez, who later left the ground limping in the 64th minute, was put through on goal in the 24th by Stein Huysegems but the Costa Rican international put his close-range attempt well wide with the net at his mercy.
Encouragingly for the Phoenix, striker Cunningham continued to look lively after he opened his A-League scoring account during last week's loss to Sydney FC.
The Costa Rican forward struggled to find his way during the early rounds of the season but is becoming more accustomed to the style of play Down Under and is beginning to build links with his fellow Phoenix players.
Today's result marked the second 0-0 draw the Phoenix have played out this season and Merrick's men are still looking for a decisive outing in front of goal.
Wellington head to Perth next Friday to meet the Glory in Western Australia.
