Chelsea have defeated Derby County to advance to the fourth round of the FA Cup.
Derby pressured their expensively-assembled opponents high up the pitch and restricted Jose Mourinho's men to little more than half-chances for the first 20 minutes.
Ashley Cole made a good sliding clearance from a teasing Craig Forsyth cross with two Derby attackers lurking in the 14th minute.
In the 23rd minute, Samuel Eto'o was released down the left flank, but the Cameroonian took a heavy touch that allowed the Derby defence to recover and clear the ball.
Two minutes later, Michael Essien sent a 25-yard effort wide of goal as Chelsea began to create a number of openings.
However, David Luiz was then caught in possession and Jamie Ward ran at the Chelsea defence before firing a shot towards goal that was well blocked by Gary Cahill.
Ramires sent a long-range effort whistling past the post before Oscar was unlucky to see his curling free kick drop on the wrong side of the post.
In first-half stoppage time, Ramires came the closest to opening the scoring when he stepped inside from the right flank and smashed a shot against the upright.
Schwarzer saved well from a deflected Ward effort, but the visitors went 1-0 up when John Mikel Obi got across his man and glanced in a header.
Chelsea doubled their lead five minutes later as Oscar fired just inside the post from inside the box. Ramires hit the woodwork for a second time with a looping shot that struck the top of the bar, but Chelsea had done enough to secure the win.