Feisty galloper Agitate went a long way towards easing a major disappointment for jockey Ric McMahon when they combined to win at Doomben on Saturday.

Agitate was sensationally backed at his first race start before going out a $1.50 favorite and running third in a two-year-old race at Ipswich.

Despite being in a cranky mood on Saturday before the start, Agitate ($4.80) was always in control before beating the favorite Grey Countess ($3.50) by two lengths in the Organdga Properties Handicap (1010m).

McMahon is the regular rider of star three-year-old Better Than Ready who was due to race in Saturday's Group One Newmarket Handicap at Flemington.

But he lost the ride to Craig Williams because he could not make the 50.5kg.

"I would have had to cut off a leg to make the weight," McMahon said.

"Naturally I am disappointed because it would have been fantastic to ride in a big race like the Newmarket.

"But this makes up for it a bit. We thought Agitate could win at Ipswich but things just didn't go his way. I am glad the owners stuck with me today," McMahon said.

Agitate is by leading Queensland sire Sequalo out of the former smart race mare Stirring.

Many of the owners of Stirring, who has been sold to Victoria, are also in the ownership of Agitate.

Jockey Michael Cahill said Grey Countess had not been able to keep in touch with the leaders early but ran on well.

Craiglea Cruz ($12) showed pace and hung on for third, a length behind Grey Countess.