Merion has lowered the colours of boom colt Chivalry by the barest of margins at Flemington to put himself in the Caulfield Guineas picture.

The Mike Moroney-trained Merion, who is tracking the same path towards the Caulfield Guineas as last year's winner Long John, held off favourite Chivalry by a nose in Saturday's Living Legends Stakes.

It justified Moroney's opinion of Merion, who is likely to head to the Caulfield Guineas Prelude before the Caulfield Guineas.

Merion is at $10 on the third line of Guineas betting with Chivalry remaining the $5 favourite.

Zebulon's fast-finishing third has elevated him to $8 second favourite.

Merion won the same maiden and Listed Anzac Day Stakes as Long John as a two-year-old and has returned at three years to win the same Listed race second-up.

"We did study that a bit," Moroney said.

"It was a fork in the road for him today. We always knew we had a really smart horse.

"He's got a lot of improvement left in him but he's a serious horse."

Steven Arnold had Merion just behind the speed before making his run in the straight on Merion.

He hit the front passing the 200m before Chivalry made his move from behind him and challenged strongly.

Jockey Glen Boss is convinced Chivalry will turn the tables when they meet again after the colt carried 1kg more under conditions of the race.

"How are they going to beat him from now on at level weights," Boss said.

"He was very good."

Stephen Baster was delighted with the return of Zebulon who hit the line strongly.