Wearing the captain's armband, with Ulises Davila on the bench, Germain opened his ALM account on Sunday with a deft finish in the 57th minute to hand the Bulls their first win of the season.
Kearyn Baccus sealed all three points with a lovely strike in the 84th minute, scoring his first goal from 112 ALM matches.
Bulls teammates celebrate Kearyn Baccus' goal in the victory on the NSW Central Coast.
"I said to the boys 'I'm gonna score a couple this year - I'm feeling good, I need a contract' and I'm just happy we got a result today," a laughing Baccus told Network Ten.
The win was particularly pleasing for Macarthur given many of their squad played in Cambodia mid-week in their AFC Cup loss to Phnom Penh Crown.
"The boys dug in today," Baccus said.
"It's difficult travelling away and then coming back and playing.
"But a big effort from the boys and I'm happy to get a goal today."
Brian Kaltak got a goal back for the Mariners, who lost Mikael Doka to a second-half knee injury, in the 91st minute.
Bulls goalkeeper Filip Kurto came up big with two crucial early saves, first denying Christian Theoharous in the sixth minute, then Angel Torres a minute later.
Shortly after, Marco Tulio dragged a shot wide.
Then in the 39th minute, Kurto crucially intervened to deny Torres again.
Mariners midfielder Josh Nisbet went down under contact from Yianni Nicolaou in the 52nd minute but his pleas for a penalty fell on deaf ears.
The pair clashed with Nicolaou shoving Nisbet, causing a brief scuffle between their teammates and earning the defender a yellow card.
Shortly after, the visitors took the lead.
Valère Germain has his first goal in the — Isuzu UTE A-League (@aleaguemen) @IsuzuUTE A-League! 🙌🇫🇷The former @AS_Monaco star fires into the top corner to give @mfcbulls the lead at the home of the champions!Follow LIVE 📰 https://t.co/sTKYZNYniM#CCMvMAC #ALM pic.twitter.com/UwMHQCFXykOctober 29, 2023
Midfielder Jake Hollman strode through midfield then slipped through Germain.
The striker, who had a lengthy career in the French top flight, made no mistake, coolly powering a shot past Danny Vukovic.
Central Coast thought they had equalised in the 63rd minute when Brad Tapp finished off an attack involving Alou Kuol and Tulio.
The referee's assistant initially ruled it offside but, after consultation, Adam Kersey awarded a goal.
Then after a VAR review, Kersey scratched the goal as Tulio was offside.
The Mariners were adamant Hollman had handballed inside the area in the 70th minute but their pleas weren't rewarded.
Baccus doubled Macarthur's lead when he latched onto a ball from Nicolaou and coolly finished across his body.
Kaltak made for a nervous finish when he put away Noah Smith's squaring ball for his first ALM goal, but the Bulls held on.
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