Bitterly disappointed Central Coast Mariners coach Alen Stajcic has refused to use excuses to explain his side's poor start to the A-League season.

Following a hard-fought 1-0 loss to Sydney FC at Netstrata Jubilee Stadium on Saturday night, Stajcic said although the Mariners can't compete with the glamour clubs, "money doesn't buy concentration".

Sydney managed just one goal in the fifth minute against the bottom-placed Mariners, but Stajcic said an improved performance is no longer good enough for his side, they want to win.

"We have a good group of players with good heart, good spirit and good work ethic, fighting for each other and I think everyone can see that," he said.

"But to ensure you get points against quality teams like this we have to up our focus and concentration.

"Game plan and technique and fitness is all good... but if you lose concentration in one or two moments you get punished."

In a positive sign for the Mariners, Brazilian forward Jair finally made his club debut after recovering from a quadriceps injury.

He had a chance late in the first half from a Sam Silvera cross, but his header went just wide and Stajcic is certain he can improve with game time.

"He had a couple of chances and he was a threat on goal," the coach said.

"For someone who hasn't played for five months and the rest of the guys are already into round 10 he did quite well.

"You can only imagine the potential when he gets a couple of games under his belt and he gets up to speed with where everyone else is at."