You might want to fully charge the battery. If it's not charging, it might be charging system fault.
i don't know ghibli system too well, but if there's a relay, it could be a bad relay or trigger connections. Check all relevant grounds, connectors etc with contact cleaners/enhancers ie deoxit, to ensure it's not a bad connection before replacing starter.
Long ago with a different car, i ran into similar problem when it wouldn't crack intermittently though a clicking noise was observed. I went thru all grounds, relay connections, fuseboxes, and cleaned every electric connectors I could find. It didn't help at time. It was getting dark so I left it sitting overnight. To my surprise it cranked right up on the first try in the morning and it continued to crank for the next 10+ years before I let go the car. The starter never missed a beat.