Shortly after the announcement this year's Fourtrackforkids charity walk had been renamed for Tommy Berry's late twin brother Nathan, the jockey claimed an emotional win at Randwick.

Berry won Saturday's opening race aboard Saigon Tea, sporting the colours of Geoff and Mary Grimish, long-time supporters of Nathan who died in April from the rare epilepsy-related Norse syndrome.

The Fourtracksforkids walk on October 6 will be called A Walk For Nathan with participants travelling from Warwick Farm to Randwick via Rosehill and Canterbury racetracks.

The Sydney Children's Hospital Network, the National Jockey Trust and Epilepsy Action Australia will be the 2014 beneficiaries.

"It's great to win in these colours and for the walk to be named for Nathan," Berry said.

Winning trainer Chris Waller donated his percentage to the cause after the mare ended a frustrating sequence of three seconds with her win over 2400m.

Sent out the $2.30 favourite, Saigon Tea overhauled race leader Tohunga ($4.60) in the straight and went on with the job to win by a length.