Grgurevic scored three medals in the 105kg men’s division; silver in the snatch, and bronze in the clean and jerk and overall, pipped for second place by New Zealand’s Rory Taylor on body weight difference.
The medal took Australia’s tally to six gold, 14 silver and nine bronze on day four of the Games.
"It's frustrating to lose on body weight. But I couldn’t be happier. It was a the biggest battle I've ever had in competition and I can learn from it and develop.
"I don’t think you can ever complain when you medal at a big event."
The 24-year-old said it was a highlight of his career.
"It's really the best international trip I’ve ever been on," he said.
"It's an excellent warm-up area plus the village atmosphere has been fantastic, I've loved all the singing by the other countries, especially Samoa."
Tasmania born, now based in Victoria, he said the hard preparation paid off.
"When you get up there you know you’ve done all the work and it’ll come together.
"This ranks in top two of my favourite events, holding the junior national record is also up there."
In the women's over 75kg division, Victorian Belinda Van Tienen marked her first international competition in five years with a solid fourth place overall.
"It was my first big competition since the 2010 Commonwealth Games, so it’s been a big break," she said.
"It's good to be back on the international platform."
The Games has marked a step up for Van Tienen, who usually competes in the up to 75kg division.
"These girls have been training at the higher body weight for a lot longer, so it makes it difficult.
"But this event has really just brought back that competitive feeling."
The 28-year-old said she'll decide after the Nationals Championships in August whether she’ll continue competing.
"I'll see how training goes if it's worth it, I’ll give it a shot. I'm enjoying lifting again. It’s hard not to be always chasing new personal bests and I always want to be competitive."
Van Tienen said the Games have been amazing experience.
"The venue is international standard and run really well. It's a really good crowd, just walking through the stadium everyone’s so friendly."
For new Australian Philip Woods, Wednesday’s over 105kg competition marks his first international Team after he took up the sport two years ago.
Born in England, the 28-year-old only became an Australia citizen three weeks ago.
"It's my first international competition and to come in and do six from six lifts. I didn’t think I'd ever achieve that," he said.
"I loved being up there, seeing all the Aussies in the crowd.
"I just love competing, having a go against the other athletes who have been lifting for years.
"The crowd was awesome, they all cheered for everyone."
Woods, Grgurevic and Van Tienen will next compete at the National Championships in August in Melbourne.
In sailing, the three Australian sailors had a successful day on the water with three more days of racing to go.
In Laser both Mark Spearman and Thomas Vincent finished first and third in the two races.
While in the Laser Radial, Carissa Bridge also finished third and first.
Across at the Sir John Guise outdoor stadium the Australian women's rugby sevens side kicked off their Games campaign with three wins from three matches.
The Team beat Fiji 26-7, New Caledonia 22-5 and Tahiti 59-0.
They'll face Tonga, Somoa and Papua New Guinea on Thursday.
Annie Kearney in Port Morseby