William Saliba was sent off late on as nine-man Arsenal U21 crashed out of the Papa John's Trophy following a resounding 3-0 defeat by AFC Wimbledon.
After an even first half at Plough Lane, the Dons took the lead through Ryan Longman, before Paul Osew doubled their lead six minutes later.
The Gunners were reduced to 10 men when Tim Akinola picked up a second booking with 10 minutes to play, with Saliba suffering the same fate shortly afterwards. In the third minute of injury-time, Joe Pigott added a deserved third.
Accrington will AFC Wimbledon in round three having recorded a scalp of their own with a 3-2 victory over Manchester United U21 at the Wham Stadium.
Cameron Burgess' eighth-minute header set Stanley on their way, but Facundo Pellistri and Anthony Elanga struck either side of half-time to put United in the driving seat, before a late double from Joe Pritchard sealed victory for the hosts.
Kieran Agard and Regan Poole scored two each as MK Dons recorded a crushing 6-0 home victory over Norwich U21, while Tranmere hit back after Liam Delap's opener to sink Manchester City U21 2-1, thanks to goals from Danny Lloyd and Oliver Banks.
Lee Johnson recorded his first win as Sunderland boss as the Black Cats came from behind to oust Oldham. Bobby Grant edged the Latics ahead after 13 minutes, before Chris Maguire and Josh Scowen hit back to seal a 2-1 win.
Paul Mullin scored his 16th goal of the season as Cambridge beat Gillingham 2-0, while Jordy Hiwula scored twice as Portsmouth sauntered to a 3-0 win away at Cheltenham.
In a repeat of June's League Two play-off final, Northampton beat Exeter 2-1 and at Brisbane Road, Bristol Rovers beat 10-man Leyton Orient by the same scoreline.
Elsewhere, Mo Eisa scored either side of 20-year-old Serhat Tasdemir's strike to earn Peterborough a resounding 3-0 win over West Ham U21, with Port Vale 2-1 winners at home to Wolves U21. Lincoln dealt Shrewsbury a crushing defeat as they ran out 4-1 winners at Montgomery Waters Meadow.
Meanwhile, there were penalty shootout victories for Leicester U21, Fleetwood, Hull and Oxford after the quartet had drawn with Salford, Blackpool, Crewe and Forest Green after 90 minutes respectively.