Abraham had an early penalty claim denied after VAR showed him falling at the feet of Caglar Soyuncu.
Rudiger opened the scoring a minute into the second half with a simple header after Mason Mount sent a curling ball towards the far post.
Leicester dominated the next 20 minutes with Barnes scoring in the 54th minute before setting Chilwell up in the 64th.
Lampard, who took the decision to drop Kepa Arrizabalaga before the game, will be left wondering if he made the right decision with Willy Caballero largely at fault for the second goal.
Rudiger once again rose to the occasion for Chelsea and secured a second header to bring the game level.