The horse carrying the heaviest weight in the field took out the big race, followed by Emissary in second and High Emocean third.
The red-hot favourite Deauville Legend had to settle for fourth.
Gold Trip brushed aside an international challenge to win the Melbourne Cup, giving one of Australia's biggest stables a breakthrough in the race.
One of five runners for co-trainers Ciaron Maher and David Eustace, Gold Trip defeated Emissary and stablemate High Emocean.The six-year-old stallion rated an 18/1 chance by bookmakers, charged in front at the 300m mark to win a thrilling sprint to the final post in the gruelling two-mile handicap.
Gold Trip was given a perfect ride by Mark Zahra, who also celebrated his first win in the race.
"I feel like crying. It’s unbelievable. What a day," said Zahra.
"He’s a horse that when you go, you don’t give him a chance to think about it. I was hoping no one would come near me. It’s just elation when I crossed the line."
The field of 24 was reduced to 22 after Point Nepean was scratched on Monday and Lunar Flare failed a veterinarian inspection on the morning of the race.
The Cup ran after police were called to investigate alleged vandalism at Flemington in the early hours of Tuesday morning, with video on social media showing a hand-held hose discharging an oily, black substance onto the track.
The Nine Network said an unnamed person contacted the broadcaster and claimed responsibility for pouring the sludge as a "problem gambler" making a protest against the Victorian Racing Club.
The Victorian Racing Club runs the Melbourne Cup and other race meetings at Flemington.
Racecourse staff cleaned up the sludge around the 1,500m mark of the track and the Cup day races proceeded without incident.
Full final leaderboard
Gold Trip
Emissary
High Emocean
Deauville Legend
Realm Of Flowers
Interpretation
Tralee Rose
Smokin' Romans
Arapaho
Grand Promenade
Daqiansweet Junior
Serpentine
Hoo ya Mal
Young Werther
Vow And Declare
Stockman
Camorra
Without A Fight
Numerian
Montefilia
Knights Order
Duais
- Additional reporting AAP/NZ Herald