Chelsea will face QPR or MK Dons away in the fourth round of the FA Cup.
The Blues dispatched Portsmouth 4-0 at Stamford Bridge, but made hard work of it. Juan Mata opened the score on 47 minutes, but the home side had to wait until six minutes from time before dispatching the South Coast side.
A brace by Ramires and a 93rd minute strike by Frank Lampard saw off Portsmouth.