Central Coast Mariners teenager Mathew Ryan is planning to take his A-League opportunity with both hands.

The 18-year old goalkeeper has come into the Mariners line-up as replacement for the injured Jess Vanstrattan who is sidelined for the rest of the season and after playing his first two games, is feeling more comfortable in the role.

"Easily the two biggest games of my career, a little bit nervous at first but all in all I think I handled the situation pretty well," said Ryan of his Sydney FC and Melbourne Victory performances.

Ryan admitted the trust placed in him by Mariners coach Graham Arnold had helped enormously.

"I can't explain how it makes me feel just having the confidence of someone like Graham, who's been coaching with the Socceroos for a good ten years," he added.

"For him to have belief in me, makes me believe in myself. Hopefully I can come out again this week and prove my worth."

The Mariners take on Melbourne Heart at Bluetongue Stadium on Friday night in Round 6 of the A-League - kick-off is at 8:00pm.