Colchester United pulled off an EFL Cup upset as they beat Premier League side Crystal Palace on penalties.
Palace, who won at Manchester United on Saturday, dominated possession but struggled to break down their League Two opponents at Selhurst Park.
That meant the game went to spot-kicks and it was Colchester who held their nerve to progress to round three.
Andros Townsend took the first penalty of the shootout, but his effort was saved by Colchester goalkeeper Dean Gerken, and that miss proved decisive as the U's scored all of their attempts, with 18-year-old Noah Chilvers slotting home the winner to spark wild celebrations in the away end.
In contrast, Premier League Norwich City were on the other end of a big shock as they lost 1-0 at League Two side Crawley Town.
The Canaries made eleven changes for the clash, and rested top-scorer Teemu Pukki, but still fielded a strong-looking team on paper.
However, they found themselves behind early on through a deflected effort from Beryly Lubala and couldn't force an equaliser.
If that wasn't enough, Head Coach Daniel Farke confirmed after the game that Timm Klose suffered a serious knee injury and could be ruled out for the rest of the season.
Elsewhere, Luton Town avenged their recent Championship defeat to Cardiff City by running out comfortable 3-0 winners against the same opposition in Wales.
An own goal by Junior Hoilett put them ahead, before second-half strikes from Alan Sheehan and Jake Jervis sealed the victory.
The Hatters will be joined in the hat by MK Dons who brushed aside struggling Southend United at Roots Hall.
The Dons scored twice in the first-half via Rhys Healey and Callum Brittain before the Shrimpers pulled one back through Brandon Goodship.
Late goals from Hiram Boateng and Sam Nombe wrapped up the win though as the Dons booked their place in the third round.