With a goalless scoreline at the break Chelsea scored four times in the second half, the home supporters nerves only be settled by three goals in the closing minutes as Portsmouth made the Blues work hard for their victory.
The last time these two sides met in the FA Cup was in the 2010 final when Chelsea were again the victors.
Portsmouth deservedly went in at the break level after making Chelsea look ordinary for most of the half with David Norris outstanding but when Juan Mata put the hosts ahead immediately after the restart it seemed as if the Blues would find their form.
But Portsmouth continued to restrict their Premier League opponents who struggled for any cutting edge and whilst the score remained at 1-0 there was always the possibility of Pompey springing a breakaway goal.
The three goals in the final six minutes ended Portsmouth’s resistance and gave the scoreline an unfair sheen in the home side’s favour.
Referee: Anthony Taylor
Venue: Stamford Bridge
TRIBAL ASKS: Chelsea boss Andre Villas-Boas knows he needs better displays than this from his team
Yellow cards: Kitson (POR), Williams (POR), Pearce (POR), Halford (POR), Malouda (CHE), Terry (CHE), Meireles (CHE), Ramires (CHE)