Williams, who made his first-team debut for Pompey in the weekend's 2-2 draw with Middlesbrough, was a 73rd-minute substitute against Barnet.

Elsewhere, James Wesolowski made his debut for new club Oldham Athletic as they were knocked out on penalties by Carlisle United 4-2 after a 1-1 draw.

Wesolowski played 86 minutes in the match, while Aussie compatriot Alex Cisak put in a full shift but couldn't save his side during the shootout.

Australian defender Aaron Downes played his first game since February 2010 as Chesterfield lost 3-2 at Rochdale, while Paddy Kisnorbo put in another full shift as Leeds United eased past Bradford 3-2.