Superstar galloper War Affair's bid for a historic clean sweep of the Singapore Triple Crown Series remains on track after drawing Gate 14 for the upcoming Group 1 Longines Singapore Gold Cup.

The four-year-old brown gelding has already won the first two legs last month, the Group 1 Kranji Mile and Group 1 Raffles Cup, and another victory on Sunday would make him the first horse in local racing history to complete the treble in a calendar year.

Despite carrying the top weight of 58kg on his back for the $1.35 million race over 2,200m, the New Zealand-bred stayer, with jockey Danny Beasley on the saddle, will likely start as favourite in a field that will feature 16 runners.

"It's not going to be easy with the wide draw and there's a lot of pressure on him to win but he's been improving with each race and I'm sure he'll run a good run on Sunday," stable supervisor Jason Ong said on the sidelines of Wednesday's Post Position Draw at the Singapore Turf Club.

War Affair is trained by Singaporean handler Alwin Tan and has an imposing record of 11 wins from 15 starts and has collected around $1.8 million in stakes earning since his debut in April 2013.

Among the other leading contenders for the 11-furlong race are the Patrick Shaw-trained Quechua (Gate 15) and the Laurie Laxon-trained duo of Goodman (6) and Stepitup (7). Last year's winner Tropaios (Gate 18) of the Michael Freedman yard will jump from the outermost alley.