Thousand Guineas winner Yosei has been retired following her failure in Saturday's Toorak Handicap at Caulfield.

The six-year-old mare failed to beat a runner home in the race she ran third in last year.

Yosei hadn't won a race since claiming the Group 1 Tatts Tiara (1400m) in 2011, one of three career Group 1s including the 2010 Thousand Guineas (1600m).

She also claimed the Sires' Produce Stakes in April 2010 as a two-year-old.