Mrs Penny started slowly and appeared to have little chance until the final furlong, but finished very strongly to overtake Abeer in the closing stages and win by three quarters of a length.
Abeer had been conceding nine pounds to Mrs Penny at Newmarket, and when the fillies met again at a three-pound difference in the Lowther Stakes at York Racecourse in August she was widely expected to reverse the placings.
Starting the 11/2[6] third choice in the betting, Mrs Penny took the lead two furlongs from the finish and won decisively by two lengths from Teacher's Pet, with Abeer in fourth place.
[2] On her three-year-old debut, Mrs Penny ran in the Fred Darling Stakes, a trial race for the 1000 Guineas, over seven furlongs at Newbury Racecourse in April and finished second, half a length behind Millingdale Lillie[7] with Quick As Lightning in third place.
[8] Lester Piggott took over from John Matthias as Mrs Penny's jockey when the filly was sent to France and moved up in distance to contest the Prix de Diane over 2100 metres at Chantilly Racecourse.
Mrs Penny was then aimed at Britain's most prestigious all-aged race, the King George VI and Queen Elizabeth Stakes at Ascot Racecourse in July.
In the Benson and Hedges Gold Cup at York on 19 August,[10] Mrs Penny was unable to obtain a clear run in the straight before finishing strongly to take fourth place behind Master Willie, Cairn Rouge and Cracaval.
[8] As Piggott was serving a suspension, Matthias reclaimed the ride on Mrs Penny when the filly was sent to France in September for the Prix Vermeille over 2400m on soft ground at Longchamp Racecourse.
Racing on firmer ground she held a good position on the turn into the straight but dropped back in the closing stages and finished fifteenth of the twenty runners behind Detroit.
[8] Mrs Penny remained in training as a four-year-old in England, but failed to recover her best form, finishing fourth behind Master Willie in the Coronation Cup and unplaced behind Pelerin in the Hardwicke Stakes.