Frank Lampard couldn't claim another memorable Carabao Cup scalp as his valiant Derby County side lost 3-2 to Chelsea at Stamford Bridge.
Rams manager Lampard was returning to the club where he made 600 appearances during his playing career, with Derby looking to add to their surprise third round win over Manchester United.
They gave a good account of themselves in a breathless and evenly-matched first half, bouncing back from own goals by Fikayo Tomori and Richard Keogh to equalise twice through Jack Marriott and Martyn Waghorn.
But Cesc Fabregas' strike gave Chelsea the lead at half time and they were much improved after the break to close out the win, although David Nugent could have taken the game to penalties when he hit the post late on.
At the London Stadium, Son Heung-min scored his first goals of the season as Tottenham won 3-1 against West Ham. Lucas Perez briefly got the Hammers back in contention after Son's brace but Fernando Llorente secured Spurs' place in the draw.
Arsenal were made to work for their victory by Blackpool but eventually overcame their League One visitors thanks to Stephan Lichtsteiner's first goal in English football and 18-year-old Emile Smith-Rowe's first at the Emirates Stadium.
Paudie O'Connor halved the deficit after Matteo Guendouzi's red card but the Gunners held on to reach the quarter finals.
Crystal Palace's poor form continued as they were knocked out by Championship high-flyers Middlesbrough. Lewis Wing's first goal for the club sent Boro into the last eight for the first time since 2012/13 and extended the Eagles' winless run to five games.
Wednesday's four winners join Bournemouth and Burton in the quarter finals, with two more ties still to be played.