Untapable can cement her status as the queen of the three-year-old fillies in Saturday’s $1 million Cotillion Stakes in Philadelphia in what figures to be an important showdown between the top two female sophomores in the US.

Untapable, a daughter of Tapit, demolished her competition in her first four starts of the year including the G1 Kentucky Oaks and Belmont Park’s G1 Mother Goose in June by a combined 31 lengths for trainer Steve Asmussen.

Her connections decided to then try the Haskell at Monmouth park against the colts but the result was a fifth as the heavy favorite.

Untapable brings a 6-for-9 lifetime record to the Cotillion and a win would go a long way in securing championship honors in the 3YO fillies division.

Her rival is Stopchargingmaria, who enters as the “now” horse for trainer Todd Pletcher off a trio of consecutive wins.

The daughter of Tale Of The Cat won Aqueduct’s G3 Tempted and G2 Demoiselle to end her 2-year-old campaign but struggled in her first two starts of 2014 before she found her form at Pimlico, winning the G2 Black Eyed Susan in May.

She then took out a pair of G1 features at Saratoga in the Coaching Club American Oaks in July and Alabama Stakes in her last start on August 16.

She brings a 6-for-10 lifetime record to the Cotillion and a win over Untapable could give her a tenuous divisional lead.

Sweet Reason, a triple G1 winner, is also a serious contender while being tested around two turns.

The winner of the G1 Acorn Stakes at Belmont in June and Saratoga’s Test Stakes at seven furlongs in her last start August 23, Sweet Reason also won Saratoga’s G1 Spinaway as a 2-year-old and was fourth in the Breeders’ Cup Juvenile Fillies.

While she has proven much more effective in one turn races, Sweet Reason would throw her hat in the ring for championship honours if she upsets the favoured pair.