Chelsea booked their place in the League Cup semi-finals with a late 2-1 win at Fulham and were joined by unfancied Watford after the second division side trounced English Premier League side Portsmouth 3-0 on Tuesday.
Premier League leaders Chelsea, who thrashed Fulham 4-1 just over two weeks ago, needed an 88th minute winner from substitute Frank Lampard to scrape a victory on their return to Craven Cottage.
Jose Mourinho's men took a 55th minute lead with a deflected shot from Ireland winger Damien Duff, only for American striker Brian McBride to level for Fulham in the 74th.
Watford, who thrashed Southampton 5-2 in the fourth round, claimed their second south coast top flight victims with two goals from Icelandic striker Heidar Helguson and a third from Bruce Dyer at Vicarage Road.
The quarter-finals continue on Wednesday with Manchester United's game against arch-rivals Arsenal and Tottenham Hotspur's home tie with Liverpool.
The final is on February 27 in Cardiff.
