Trailing 29-28, England sent on Shane Geraghty at fly-half and Rob Webber at hooker, while fellow replacements James Haskell, Ben Youngs and Dan Ward-Smith also appeared on the hour.
As well as youngsters such as Ben Youngs, Chris Ashton, Ben Foden, Dan Cole and Courtney Lawes forcibly asserting their Test credentials, Johnson also took heart from the contributions of others to the second-string side.
Leicester were missing their England quartet Toby Flood, Ben Young, Dan Cole and Tom Croft, but Jordan Crane returned on the bench following a pre-season ankle injury, where there was also a place for loan scrum-half signing Jason Spice.