Wilfried Zaha proved the goal hero for Crystal Palace, while Charlton and Bristol Rovers upset Reading and Watford.
Championship side Crystal Palace overcame League Two big spenders Crawley Town thanks to a quick-fire brace from Zaha.
The 18-year-old striker notched in the 54th minute and then four minutes later to send the Eagles soaring into the second round.
League One's Charlton upset the odds against Championship Reading.
Paul Benson notched the opener for the hosts in the 25th minute and Jason Euell added a crucial second on 64 minutes.
Sean Morrison pulled one back for the Royals but the Addicks held on to continue their unbeaten start to the campaign.
The clash between League Two's Bristol Rovers and Championship Watford went to extra-time and then penalties after early goals from Marvin Sordell and Matt Harrold left the tie level after 90 minutes.
The Pirates then felled the Hornets by holding their nerve to win 4-2 on spot-kicks.