Among Fat Al's owners are Waterhouse's daughter Kate and her husband Luke Ricketson, who were on hand to see Berry take favourite Fat Al ($4.60) to the lead out of the barriers.
Under hard riding, Fat Al denied Ambidexter by a head with Rolling Pin ($41) third, 1 lengths further back.
Topweight Shoot Out ($6) was the best of premier trainer Chris Waller's trio, finishing seventh with Said Com ($17) 11th and Rangirangdoo ($12) 12th.
Waterhouse said Fat Al had been appropriately named as a young horse but had blossomed as he got older. "He was a roly poly horse when he started and two years later he is here winning an Epsom.
"I'm privileged to train him."
Berry said he had been caught by surprise by how close Ambidexter got to him. "I knew Rolling Pin was there but Ambidexter caught me by surprise. He got to me but I don't think he got past me."
Last year's winner Secret Admirer made ground late to finish fifth, 2 lengths from the winner.
She carried 54kg compared with the three placegetters who all had 52kg, which her jockey James McDonald said was a telling factor.
"She ran home really strongly but it was just too big a task to give away the weight to those 4-year-olds."
Berry's twin brother, Nathan, was on another of the Waterhouse runners, Kontiki Park, who trailed the 15-horse field, while stablemate Wild And Proud finished 10th.
Apprentice Chad Schofield, who replaced an ailing Christian Reith on the Gwenda Markwell-trained Rolling Pin, was fined $200 for overuse of the whip.
- AAP
