Brighton moved into the FA Cup quarter-finals for the second successive season as goals from Anthony Knockaert and Jurgen Locadia clinched a 2-1 win over Derby on Saturday, while Millwall also won through.
Chris Hughton's side have been sucked into relegation danger in the Premier League after six games without a win.
But the Seagulls made the most of a welcome break from the grind of the relegation battle as they saw off Frank Lampard's Championship side at the Amex Stadium.
Derby had claimed the scalps of Manchester United and Southampton in domestic cup competitions this season.
But the fifth round tie was tipped in Brighton's favour by a dominant first-half display.
Brighton opened the scoring after 33 minutes when Knockaert bent his first-time shot into the bottom corner of Kelle Roos' net after connecting with Yves Bissouma's cross.
Hughton's team doubled their advantage when Locadia fired home from close-range in first-half stoppage time after Bissouma's effort hit the post.
Former Chelsea and Arsenal star Ashley Cole set up a tense finish when the Derby defender headed in after 81 minutes.
It was the 38-year-old's first goal in England since 2012 and his first ever in the FA Cup and the landmark strike came in his second game since joining Derby until the end of the season following his release by LA Galaxy.
But, despite Derby's barrage of pressure, Cole's goal wasn't enough to spark a late escape for the Rams.
Championship strugglers Millwall are also through to the quarter-finals after a 1-0 win at AFC Wimbledon.
Separately, AFC Wimbledon, currently bottom of League One, enjoyed a memorable win over West Ham in the fourth round.
But Neil Harris's side avoided becoming their latest upset victims as the Lions made it to the last eight for the second time in three years.
AFC Wimbledon's Joe Pigott hit the post from close range in the opening moments and Millwall made the most of that let-off to take the lead in the fifth minute.
Ryan Leonard made a barnstorming run down the right and whipped over a teasing cross that Scottish defender Murray Wallace converted with a powerful header at the far post.
Wallace also scored Millwall's last-gasp winner against Everton when the 2004 FA Cup finalists' came from behind for a shock fourth round victory. (AFP)
Last updated: 2019-02-17 HKT 02:53