Alvaro Morata scored double as holders Chelsea began their fa Cup defence with a 2-0 win over Nottingham Forest in a match where a tearful Cesc Fabregas appeared to bid farewell to English football.
The third round is the stage where topping clubs enter the world's oldest senior knockout soccer tournament and has traditionally been related to upsets.
But after Saturday's afternoon matches, the lone giant-killing act had seen third-tier Gillingham beat Premier League Cardiff 1-0, whereas second-tier derby, managed by former England midfielder Frank Lampard, came from 2-0 down to draw 2-2 with top-flight strugglers Southampton.
Both Morata and Fabregas have been coupled with moves faraway from Stamford Bridge in the Jan transfer window, the latter is reportedly set to join a Monaco facet managed by former Arsenal mate Thierry Henry.
Fabregas should have opened the scoring in the 30th minute however his poor penalty, after a foul on Ruben Loftus-Cheek, was saved by goalkeeper Luke Steele.
But 2 goals in the space of ten minutes early in the last half from Morata, who had antecedently lost some clear possibilities, settled the tie.
Teenage prospect Callum Hudson-Odoi was the provider on both occasions, his cross to the close to post fitting Morata for his initial goal since November 29th in the 49th minute before the striker made it 2-0 with a header.
Cardiff fa Cup finalists 11 years ago, conceded minutes from time when Gillingham midfielder Elliott List beat reserve goalkeeper Alex Smithies before the hosts survived quite eight minutes of extra time.
It appeared Southampton were cruising into the fourth round following goals early in each half by Nathan Redmond but derby hit back with 2 in fast succession after the hour mark through Jack Marriott and Tom Lawrence.