Paul Merson's cross from the right was knocked down by Emerson for the former Crewe midfielder to shoot through Keith Branagan's legs.
Alan Thompson drew first blood for Bolton after 33 minutes, but Mark Summerbell's equaliser ensured the game would go to extra time
A goal by Tony Mowbray in the third minute of extra time put Ipswich into the quarter- finals for the second consecutive year. Andy Legg deceived Oxford's defence by taking a short throw-in instead of launching the ball into the penalty area and nobody picked up Kieron Dyer, whose cross was headed in by Mowbray.
In the Nationwide League First Division, John McGinlay scored his first goal since moving across the Pennines from Bolton a fortnight ago to earn a deserved point for Bradford in the Yorkshire derby against Sheffield United. The Scottish striker cancelled out Brian Deane's opener minutes earlier.
Watford, the Second Division leaders, claimed another three points with a gritty 2-1 victory over Oldham through Tommy Mooney's 83rd-minute winner. David Thomas's goal after five minutes gained the initiative for Graham Taylor's side, but Lee Duxbury's equaliser after 56 minutes had appeared to salvage the match for the visitors before Mooney's late strike sealed the game.
Despite their success, Watford have not put further distance between themselves and second-placed Bristol City. Two first-half goals in as many minutes by Mickey Bell, lifted City to a 2-1 win over Plymouth. Carlo Corazzin pulled one back after 83 minutes, but City survived the visitors' late pressure to remain six points behind Watford.
Northampton restated their claims for promotion to the First Division by moving into third place with a 4-0 drubbing of the bottom club, Brentford. Carl Haggs and John Gayle sparked Ian Atkins' side into action with goals in the first 10 minutes, and their Australian striker, David Seal, effectively shut the door before the break with goals after 40 and 43 minutes.
Paul Peschisolido's value to Fulham was underlined against York. Tony Barras had given the visitors a 19th-minute lead from a penalty only for the Canadian striker's 57th-minute equaliser to earn a share of the points at Craven Cottage.Reuse content