In a field with many stayers resuming, Sam Clipperton let Complacent make his way to the lead and the 5-year-old didn't falter, beating Royal Descent by a soft 1 lengths.
Royal Descent's Doncaster Mile-winning stablemate Kermadec finished a further 1 lengths third, with Hartnell fourth.
The winner's trainer, John O'Shea, said the plaudits belonged to the stable's vets who had persevered with Complacent, who spends most of his time in the country surrounds of Godolphin's Osborne Park property in northwest Sydney.
"We were thinking about giving him a run in the autumn and I wasn't quite happy with him and we ran out of races," O'Shea said. "Our vets and all the team at Osborne have worked on this horse for two years.
"It's been an unbelievable performance from everyone there. He's a great horse. You only need to look at his record."
O'Shea said he preferred to keep Complacent close to home.
"If he's going to run in a Cup, he'll run in the Caulfield Cup and that would do him. I don't really want him too far away from Osborne."
Clipperton said he let Complacent tell him how to run the race.
"He's a big, strong horse and you can't fight him too much," he said.
"I just let him build up momentum and he just kept building and building and building."
Waller was proud of his team, many of which are heading to major staying races this spring.
"Royal Descent was maybe a bit flat second-up after her Warwick Stakes win but she still finished the race off well. I'm very pleased with Kermadec and the others are heading in the right direction."
Further south, The Cleaner and his trainer, Mick Burles, will have another shot at trying to win the Cox Plate after claiming the Dato Tan Chin Nam Stakes for the second year in a row.
After defying his rivals in Saturday's weight-for-age race at Moonee Valley, The Cleaner returned to scale to the applause of the crowd and the adoration of his trainer.
Left behind him was multiple weight-for-age winner Contributer, who finished fifth as the $2.20 favourite in his spring return.
The Cleaner was one of racing's best stories during last year's spring carnival as he won his way to the Cox Plate.
He finished ninth after a wide run early from a deep barrier, and his win on Saturday carries with it another ballot exemption into this year's A$3 million race.
The 8-year-old gelding's best mate Burles, who trains The Cleaner at Longford in Tasmania and takes him across Bass Strait on a ferry for each Melbourne start, is convinced the galloper is bigger and stronger than ever.
Jockey Noel Callow worked The Cleaner ($5.50) to the front and later started to click him up from the 600m.
He led by two lengths into the straight and was never challenged in beating Bagman by 1 lengths with a long neck further back to Dibayani third.
Spring stars wind up
•Chris Waller lined up 11 horses in the Chelmsford Stakes but was upstaged by Godolphin, which had only two runners in the event.
•2013 Spring Champion Stakes winner Complacent returned to the winning list after a lengthy layoff.
•Tasmanian hero The Cleaner ran his rivals ragged to win the Dato Tan Chin Nam Stakes.