"I don't want to keep them grounded," Merrick said of his players.
"I want to keep them excited, positive and looking towards scoring goals and playing in front of, hopefully, the biggest crowd of the year at Westpac Stadium on Sunday night."
The Scotsman nearly has a full quota of players to pick from, aside from veteran striker Joel Griffiths who is done for the season due to a serious knee injury.
Merrick has a couple of selection headaches in terms of the make-up of his backline, particularly his fullbacks, or whether to push the versatile Louis Fenton in to the midfield where he was so effective against the Mariners.
Fenton's move up the paddock was a game-changer for Merrick as he sparked the side towards their comeback, which wasn't completed until deep in stoppage time when Kenny Cunningham completed his brace and found the winner.
"We want to be able to hold the ball in midfield. Win it and hold it and service the strikers up front," Merrick said. "They're all competing for a spot."
Merrick may opt for the more steady Vince Lia, who is a proven performer in winning the ball, and Alex Rodriguez's form has been mixed for much of the season.
Regular left back Manny Muscat was dropped last week but will be pushing for selection too.
Sydney FC are an imposing outfit and boast golden boot leader, and Austrian national skipper, Marc Janko in their ranks.
The 1.96m forward has scored 16 goals this summer, three ahead of Phoenix striker Nathan Burns.
"They've got a good record away from home," Merrick said of Sydney.
"So we respect the team and what they've done and it's great to be competing against the likes of Sydney in the run in to our first finals game."
If Sydney were to win tomorrow, they would hold on to second place on the ladder so they also have plenty to play for. Melbourne Victory have all but claimed the Premiers Plate.
Meanwhile, an offshore report this week linked Cunningham, a Costa Rican international, with a move away from the Phoenix at the end of the season but Merrick brushed it off as speculation given the campaign was nearly over.