Two late Matthew Barnes-Homer goals saw non-league Macclesfield pull off a massive upset over Championship leaders Cardiff as they triumphed 2-1, with the striker levelling in the 85th minute before his last-gasp penalty clinched the win.
Conference side Luton were another club to pull off an upset as they edged out Championship strugglers Wolves 1-0, with Alex Lawless firing them to the surprise win.
Premier League champions Manchester City eased into the fourth round with a routine 3-0 home win over Championship Watford. Roberto Mancini named an almost full-strength side at the Etihad Stadium and his decision paid dividends as Carlos Tevez and Gareth Barry scored, with young debutant Marcos Lopes completing the haul off the bench late on.
Fulham denied Blackpool a shock success as Giorgos Karagounis equalised for a 1-1 draw to set up a replay. Ludovic Sylvestre had put the Championship club on course for a surprise triumph on the hour mark at Craven Cottage.
Championship rivals Leeds and Birmingham will also meet in a replay after Luciano Becchio cancelled out Wade Elliott's opener in the 60th minute to seal a 1-1 draw at Elland Road and take his personal tally to five goals in as many games.
Alex McLeish is still seeking his first win as Nottingham Forest manager as his side were upset 3-2 at home by League One Oldham after going down to 10 men. Robbie Simpson scored a double for the visitors in a game which saw Danny Collins shown a straight red card on the hour mark for a foul on Matt Smith.
Championship high-fliers Hull City face a replay against League One Leyton Orient after snatching a 1-1 draw thanks to Nick Proschwitz's equaliser.
Non-league Hastings United saw their impressive cup run brought to a halt at Middlesbrough as they were seen off 4-1. The Arrows had won six ties just to reach the third round but their cup dreams came to an end as Merouane Zemmama's double inspired a home win.
Leicester saw off League Two visitors Burton Albion 2-0 in the East Midlands derby at the King Power Stadium, with Chris Wood drawing first blood in just the third minute before Ritchie de Laet added another as the Foxes progressed.
Championship side Millwall saw off League One visitors Preston North End to progress thanks to Liam Feeney's 31st-minute winner.