Proisir sprinted better than his Kiwi rival to pinch a break but It's A Dundeel's stamina shone through and he knuckled down to his task, reeling Proisir in to post a thrilling short neck victory.
Honorius ($21) was five lengths away third.
"It was a great race, two great colts fighting it out like that," Baker said.
"He's only small. I've got a half-sister to him at home and she's bigger than him and she's only a yearling.
"He's got a big motor. He knows how to hit the line. He can really run that last 100m."
It's A Dundeel will head to Melbourne for the Victoria Derby (2500m) and while he is still in the Cox Plate mix, Baker says he is unlikely to head to the weight-for-age championship.
James McDonald rode the winner and had no doubts he would run the Derby trip.
"He silenced a few critics today. He's underrated," McDonald said.
"He's going the right way into the Derby. He has a great will to win.
"He will get the 2500m."
Rawiller wasn't disappointed in Proisir. He viewed stewards' footage of the finish to see if there were any grounds for a protest as It's A Dundeel was green in the straight.
But correct weight was declared.
"I thought Proisir was brilliant. Not much went our way," Rawiller said.
He also paid tribute to It's A Dundeel.
"He's an exceptional stayer. It took one to beat us, to be honest."
Meanwhile, Bart Cummings' first visit to the races for the spring worked like a charm with Norzita bringing up group one win No. 265 for the master trainer in the Flight Stakes.
Cummings has been an absentee after undergoing Nasal surgery which has affected his eyesight but not his wit.
Norzita was denied victory in the group two Tea Rose Stakes two weeks ago when Longport was awarded the race on protest but there was no mistaking the result in the Flight (1600m). "Justice has been done," Cummings said.
Longport ($14) led into the straight but had little answer when Norzita ($5.50) charged her down and drew away to win by 2 lengths.
Dear Demi ($5.50) was another 1 lengths third, with favourite Urban Groove ($2.80) finding the step up in distance and class too steep, finishing fourth. Cummings is planning his 266th group one with Norzita in the Thousand Guineas at Caulfield on Wednesday week.
"The Thousand Guineas looks ideal," he said. "When they are winning you keep them going."
Hugh Bowman replaced Corey Brown on Norzita and showed his excitement when he stood up in the irons and saluted the crowd.
"This filly was travelling so well a long way out and just felt so strong."
The Cummings-trained Duet finished fifth and the trainer also has group one ambitions for her.
"I think she might be an Oaks filly this spring," he said.
"She looks like a stayer."
Dear Demi's mission is the Oaks and trainer Clarry Conners is hoping for better luck over further after the filly was trapped wide and further forward than expected.
"It's disappointing," he said. "We didn't want to be up there.
"James [McDonald] didn't want to be trapped wide so he went forward.
"He said she wants 2000m now and he might be right. AAP
