It was the kind of form that had him turning heads at the 2011 Under-20 World Cup, when his rearguard displays helped the New Zealand side to 1-1 draws against Uruguay and Cameroon.
It looked like the world was at his feet then - but it did not quite work out that way. He had been established on the professional scene in Germany but it was a hard road. The European nation produces top goalkeepers in huge quantities, so it is a tough place to make your mark.
Marinovic found himself on the bench for long periods - at one stage playing just two matches across three seasons - and started to question if his football aspirations were realistic.
"It was tough," Marinovic said. "You wonder if you are doing the right thing and I certainly did. There were periods when I thought it might be best to forget about it all and come back to New Zealand and find something else to do with my life."
In the 2011-2012 season at German third division club SV Wehen Wiesbaden, he did not make a single first-team appearance. He moved to FC Ismaning where he spent most of the season on the bench. He then transferred to Bundesliga club 1860 Munich but appeared in only one match for the reserve team.
"There is huge competition in Germany so you need to wait for your chance," Marinovic said. "But sometimes it felt like it would never come. Of course, then you lose some confidence in your own ability."
The final roll of the dice was a move to SpVgg Unterhaching before the start of this season. The club, on the outskirts of Munich, is known for promoting young players.
"When I joined, I heard that their first-choice keeper was likely to move in the January [transfer] window. It was a strong motivation. I worked really hard, got myself fit and ready for an opportunity."
He made his first-team debut in February and has since played eight matches. It is a decent standard - the club can draw crowds of up to 15,000 - and Marinovic is getting many opportunities to impress as his team is languishing near the relegation zone. The club also have a higher than usual profile as the brothers of World Cup winners Mario Goetze and Mats Hummels are on the roster.
Marinovic was one of several impressive performers in Seoul. New defender Themistoklis Tzimopoulos showed he will be a good investment for the future, and Clayton Lewis - who recently turned 18 - put in a fearless display on the left side of midfield.
Marco Rojas looks revitalised after his move to Switzerland and both Bill Tuiloma and Deklan Wynne, who will be cornerstones of the New Zealand under-20 team at the upcoming World Cup, were superb.
Michael Burgess travelled to Korea with assistance from ASB, the principal partner of New Zealand Football.
