Pebbles faced Bob Back again in the Eclipse Stakes at Sandown, a race which no filly or mare had won since its inception in 1886. Commanche Run was a late withdrawal from the race, but the field included the Coronation Cup winner Rainbow Quest, who started 4/5 favourite. Brittain was worried that the filly's temperament would lead her to become over-excited and deliberately brought her into the paddock late. Pebbles was then re-plated, which Brittain later admitted was a deliberate ploy to delay the race and give her time to relax. Pebbles tracked the pacemaker August until accelerating into a clear lead early in the straight. According to Timeform, she "never looked in the slightest danger" and won easily by two lengths from Rainbow Quest, who went on to win that season's Prix de l'Arc de Triomphe. Pebbles was expected to run next in either the King George VI and Queen Elizabeth Stakes or the Budweiser Million, but for unexplained reasons, she lost her appetite after her Eclipse win and Brittain decided to rest the filly until autumn.
