Riverina had the chance to shock the A-League club after two narrow misses saw them fail to grab the lead heading into the break.

But the Mariners showed their class to score three goals inside the last 20 minutes of the game against Riverina's second choice side to put a gap in the final margin.

Coach Royston Thomas praised the entire side's effort given the playing talent they were up against.

"Overall the Mariners were very impressed with the majority of the players, if we were there to win the game we would have gone very close," Thomas said.

"We were only down 1-0 with 20 minutes to go and I was going to put the (first side) boys back on, but I thought the other guys had just gone on, they'd come all this way for more than 15 minutes."

The Mariners had nine youth international players in their squad this week, and their opening half goal was scored from 35m out from a player who has recently agreed to terms with Sheffield United in the English Premier League.

"The main thing is that they were interested in (Yoogali Soccer Club's) Scott Graham, they were asking about him so who knows what might happen, but that was our mission from the start to get them maybe interested in one of our players," Thomas said.