Fleetwood Town cruised past last season's Johnstone's Paint Trophy winners Crewe Alexandra with a flurry of goals either side of half time at Highbury.
David Ball and Jon Parkin both scored before the break for the home side, while Nathan Pond extended their advantage at the start of the second, before Matty Blair rounded off the win in stoppage time.
An own goal from Martin Taylor and a Grant McCann penalty helped the hosts to a two-goal lead, but Ben Nugent kept the visitors in contention with a goal inside the final 10 minutes. However, his teammates were unable to find an equaliser.
Swindon Town came from behind to beat Plymouth Argyle 2-1. Andre Blackman put the visitors ahead after just seven minutes, but Jack Barthram ensured that Swindon were level at half time, before Nick Ajose's winner early in the second half.
Rotherham United secured a comfortable victory at Bootham Crescent, beating York City 3-0. An own goal from Chris Smith gave the visitors the lead, before second-half efforts from Kieran Agard and Alex Revell ensured that the Millers eased into the next round.
Carlisle United edged past Morecambe on penalties in a closely-fought tie at the Globe Arena. After a goalless 90 minutes, both sides made a strong start to the shootout, but a couple of misses by the hosts ensured that Carlisle progress.
Matt Bloomfield and Billy Knott gave the hosts a two-goal lead at half time before Brendan Moloney got one back for the visitors, but it was not enough to stop one of the tournament's favourites from being knocked out.
Gary McSheffrey scored inside the final 20 minutes to see Chesterfield past Mansfield Town this evening. Martin Riley had a good chance for an equaliser late on for the home side, but Tommy Lee was able to parry the ball away.
A first-half strike from Joe Rafferty was enough for Rochdale to move past Port Vale. The visitors took the lead just before half time, while Port Vale had few chances to get back on level terms in the second half.
Results in full: Crawley Town 2-3 Newport County, Port Vale 0-1 Rochdale, Leyton Orient 0-0 (4-2 on penalties) Coventry City, Peterborough United 2-1 Brentford, Fleetwood Town 4-0 Crewe Alexandra, Morecambe 0-0 (3-4 on penalties) Carlisle United, Preston North End 0-2 Oldham, York City 0-3 Rotherham, Sheffield United 0-1 Hartlepool United, Wolverhampton Wanderers 0-0 (1-3 on penalties) Notts County, Mansfield Town 0-1 Chesterfield, Oxford United 1-2 Portsmouth, Swindon Town 2-1 Plymouth Argyle, Wycombe Wanderers 2-1 Bristol City, Southend United 2-5 Dagenham & Redbridge, Stevenage 2-1 MK Dons