Poor form in training led to her starting at odds of 50/1 for the St Leger but she created a huge upset by defeating the Epsom Derby winner Ladas.
[10] At Sandown Park on 20 July she was matched against top-class weight-for-age competition in the ten furlong Eclipse Stakes and finished fourth behind Isinglass, Ladas and Ravensbury.
It was believed in some quarters that Throstle had been entered in the race purely to make the pace for her stablemate Matchbox who had finished second in the 2000 Guineas, Derby and Grand Prix de Paris.
[14] She was in fact intended to run on her own merit but in two private trial gallops against Matchbox the filly had been badly beaten in the first and then bolted in the second, leading her connections to believe that she had no real chance in the race.
[15] The odds-on favourite was the colt Ladas who had won both the 2000 Guineas and the Derby Stakes and was therefore attempting to complete the Triple Crown while only others of the eight-runner field to start at less than 20/1 were Amiable and Matchbox.
Throstle, however, was making steady progress on the outside, moved into second place approaching the final furlong and wore down the favourite in the closing stages to win by three quarters of a length.
[18][19] The filly made her penultimate start in the Duke of York Stakes, a handicap over one mile at Kempton on 6 October in which she carried 121 pounds and finished fourth behind St Florian.
[20] Throstle ended her racing career in the Selection Stakes at Sandown thirteen days later when she finished last of the three runners, beaten half a length and a neck by the four-year-old Best Man and Avington.