[5] On 10 October the filly was partnered by the trainer's son Donnacha O'Brien when she started the 8/11 favourite for a maiden over one mile at Thurles Racecourse and recorded her first success as took the lead two furlongs from the finish and drew away to win by seven lengths from Indian Lilac.

[6] For her final run of the season Peaceful was sent to England to contest the Listed Montrose Stakes on heavy ground at Newmarket Racecourse on 2 November and started the 3/1 favourite in a seven-runner field.

Peaceful settled in second place behind the outsider Valeria Messalina before gaining the advantage a furlong and a half from the finish and stayed on well to win by two lengths and a head from Fancy Blue and So Wonderful.

After racing in mid-division she briefly struggled to obtain a clear run before finishing strongly to take third place, beaten a short neck and a head by Fancy Blue and Alpine Star.

[11] In October the filly was sent to Newmarket for the Sun Chariot Stakes but was reportedly unsuited by the heavy ground and finished last of the twelve runners behind Nazeef, beaten twenty-seven lengths by the winner.

[12] For her final run of the year Peaceful was sent to the United States to contest the Breeders' Cup Filly & Mare Turf at Keeneland on 7 November but made little impact, coming home eleventh of the thirteen finishers behind Audarya.