The Caulfield Cup dream is alive for the connections of Magnapal after the improving stayer booked his place in the $3 million race with victory in the MRC Foundation Cup.

The winner of Saturday's Group Three MRC Foundation Cup (2000m) at Caulfield earned a ballot exemption into the Caulfield Cup and the Terry and Karina O'Sullivan-trained Magnapal continued his unbeaten run this campaign with a narrow win over The United States.

Terry O'Sullivan has been training since 1972 and Magnapal will be just his second Caulfield Cup runner after Dolphin Jo finished 15th in 2008.

"I'm just rapt to get this little horse into the Cup," O'Sullivan said.

O'Sullivan said Magnapal was a horse which had continued to improve and he knew when he returned from a good spell that the gelding had come back better again.

"He has gone up a notch," O'Sullivan said.

"I'm still not saying he's good enough to win the Caulfield Cup but we'll be pretty happy to have a crack at it."

O'Sullivan again praised the ride of Luke Currie who is unbeaten on Magnapal and Currie brought up a winning double on the program after guiding Don't Doubt Mamma to victory.

Racing Victoria's chief handicapper Greg Carpenter will announce on Monday whether Magnapal will receive a weight penalty for the Caulfield Cup.

Magnapal has 50kg which Currie said was too light for him.

"Fifty-one, I would be a chance," Currie said.

Currie had Magnapal well positioned in sixth, one off the fence with Kapour leading and The United Stakes in the second half of the field.

Magnapal, who firmed from $6.50 to $5, angled into the clear off the leaders' backs at the top of the straight while The United States ($4.60) sprinted through closer to the inside to challenge but just missed by a head.

Genuine Lad was a half length away third.

"He went super," jockey Damian Lane said of The United States.

"He just got held up for a touch too long."