The highlight was his first century, a match-saving 100 against Warwickshire at Dudley in a game in which Worcestershire, having been set 269 to win, were in dire straits at 245/9 when stumps were drawn.
In all he made 559 first-class runs at 26.61, recording very similar figures in his 1949 season in which he hit 96 against Kent.
For the next ten years Ainsworth continued to appear occasionally, at first for Combined Services but latterly exclusively for Free Foresters.
In 1958 he made 76 and 106 for the Free Foresters against Cambridge University, and also took his second and final wicket for Combined Services against Warwickshire.
A year later, he made his highest first-class score of 137 for Free Foresters against Cambridge University, eventually being caught by Henry Blofeld off the bowling of Simon Douglas-Pennant.