A potential FA Cup classic could emerge if Arsenal turn out victorious against Leyton Orient in their fifth-round replay, as the winner will face Manchester United at Old Trafford in the quarter-finals.

The two have produced many upsets and classics in their previous meetings in the tournament, and is one of the greatest rivalries in the English game.

In the last meeting between the two, United caused a major upset with the manner of their victory after they cruised past Arsenal 4-0 in the fifth round in February 2008 before which they met in the final of 2005 when the Gunners won on penalties.

Earlier on Sunday, Arsenal were held by League-One side Leyton Orient who equalized at the depth to earn a replay at the Emirates. The winner will face United, while Birmingham has been handed a quarter-final encounter against Bolton. 

Elsewhere, Notts County were subject to a 5-0 thrashing at the hands of Manchester City in the fourth-round replay, and will face Aston Villa in the fifth round, the winner of which will face Everton or Reading in the quarters. The other tie sees Stoke at home against the winner of West Ham against Burnley.